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1. Line 3 Not Selected Temperature Range deg F Starting 100 Ending 200 Incremental 5 BePerf 62 131 ubricant Properties Comparison Options x Axis Posse Linear Log ee aaa Light WG 32 centiPoise IE Medium VG 48 centiStake Specific Gravity Weight Density Specific Heat Absolute Viscosity centiPoise 140 160 Temperature deg Y Axis Linear Log DTE Light VG 32 o Mabil DTE Medium VG 46 s 27 ug e CL oar m mw a ce m c 4 a 5 B4 Temperature deg C Y Axis Data C Reyns CentiPoise CentiStake Linear Linear C Spectic Gravity Linear Log weight Density Log Log Specific Heat Grids Minor Scaling Manual Scaling 2 min a0 Y min max f 00 Y max A div Y div BePerf 63 131 Flow Calculation Table of Contents Flow Calculation Two convenient tools for flow calculation are provided in this program One is the for Orifice Flow calculation and the other is for Chamfer Flow Calculation DyRoBeS_BePerf Untitled Seles Project Fixed Lobe Tilting Pad Flaating Ring Gas Brg Thrust Tools View Help Edit Lubricant Library Lubricant Properties Lubricant Charts Orifice Flow Chamfer Flow Calculate orifice Flow Orifice Flow This dialog box calculates the oil flow through orifices Flow Calculat
2. 0 026258 mm 2 do 0 1828 mm for Cd Total Flow Rate 0 20016 Liter Mi 06 AG 01 5295 i Pumping Loss Friction Loss Speed rpm 1000 Used in Friction Loss 0 00345 kw 0 12 kw Hecess Depth 127 BePerf 57 131 Hydrostatic Journal Bearing Design Tool Convert Units English psi Lbm in 3 of Recesses Axial Slot 0 degree Journal Dia D 3 Circumferential land b 11 43 degree Axial Length L 3 Axial side land width a 0 2 0 06 Rec 49 51 deg 2T heta 60 00 deg b 0 30 in Brg Radial Clr Cb 10 0012 9 g Supply Pressure Ps 150 Restictor Constant Flow Recess Pressure 78 Pr Ps 0 5000 Required for Flow and Power Loss Analyses Results Viscosity 5e 006 Reyne Stiffness 1 4775E 06 Lbf in Constant Flow Restrictor Total Flow Rate 0 05287 GPM Pumping Lass Friction Loss 0 00463 hp 0 161 hp Speed rpm 1000 Used in Friction Loss Recess Depth 10 05 Hydrostatic Journal Bearing Design Tool Convert Unita Metric mm deg MPa gram CE of Recesses E Axial Slat 0 degree Journal D 76 2 Circumferential land b 11 43 degree Axial Length L 76 2 Axial side land width a 5 08 a L 0 067 49 51 deg 2T heta 60 00 deg b 27 54 mm Brg Radial Clr Cb g g Supply Pressure Pa 1 03421355 Restrictor Constant Flow Recess Pressure Pr 0 517106775 Pr Psz 0
3. Pressure Dam Bearing L 5 D 5 C hz 0 005 preload 0 offset 0 Rotor Speed SOOO rpm 0 3311 Attitude Angle 69 61 HminiCb 0 6689 Maximum Film Pressure 254 4 16 deg Frictional Power Loss 6 868 Stifness 1 14199E 06 2 747E 06 5 34946E 05 1 042 06 Damping 9 572 03 2 012E 03 2 014E 03 3 405E 03 Critical Journal Mass 13 04 rpm 5000 E Cb 0 3311 Pressure 254 4 3D Pressure Profile Theta BePerf 68 131 Examples Table of Contents Examples There many examples provided in the example directory Some examples are described below but there more examples in the DyRoBeS Example directory You are encouraged to go through all the examples Example 1 2 Axial Groove Bearing File Brg 2 Axial Groove Coorl LDI Lund Coordinate System File Brg 2 Axial Groove Coor2 LDI Standard Coordinate System File Brg 2 Axial Groove Coor2 LDI Metric Units This example is taken from Shapiro amp Colsher Sixth Turbomachinery Symp 19779 It is a 2 axial groove bearing as shown below DyRoBeS BePerf C MyFolder DyRoBeS Example WBePerfibre_ Axial_Groove Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help M Example from Shapiro amp Colsher Sixth Turbomachinery Symp 1979 English Units Bearing Data L 5in Ds 5 in Ch 0 0025 in 2Cb D 0 001 Cp 0 0025 in Preload 0 Offset 0 Thet
4. 0 0006 inch Stat 82800 0 Ine 10000 Ambient Pressure n4 psi Pressurized Feed Pressure psial Side Pressure 147 8 147 Number of Pads Number of amp xsial Elements 4 90 210 0 5 0 5 20 330 0 5 0 8 25 0 5 0 5 25 Dynamic Viscosity 2 009 Some results are shown below Gas Journal Bearing Data Options Profile A 3 Lobe Gas Bearing L 1 in D 1 in Cb 0 0006 in 2Cb D 0 0012 m 0 5 tilt 0 5 Speed 82800 rpm Load 12 9 Lbf W LD 12 9 psi Vis 2 7E 09 Reyns Lamda 6 6358 Sb 0 20058 E Cb 0 6275 Att 29 05 deg hmin 0 253 mils Pamb 14 7 psi Pmax 27 868 psi g Hp 0 0439035 hp Stiffness Lbf in 3 222 04 7 65632E 03 1 932 03 6 554E 04 Damping Lbf s in 1 068E 00 3 080E 01 4 583E 01 1 205 00 Critical Journal Mass Lb Stable BePerf 103 131 Gas Journal Bearing Data Options Profile A 3 Lobe Gas Bearing L 1 in D 1 in Cb 0 0006 in 2Cb D 0 0012 m 0 5 tilt 0 5 rpm 82800 0 6275 Amb Pressure 14 7 Max Pressure g 27 868 oD Pressure Profile Gas Journal Bearing Data Options Profile A 3 Lobe Gas Bearing L 1 in D 1 in Cb 0 0006 in 2Cb D 0 0012 m 0 5 tilt 0 5 Theta rpm 82800 E Cb 0 6275 Amb Pressure 14 7 Max Pressure g 27 868 3D Pressure Profile BePerf 104 131 Nomenclature Table of Contents
5. BePerf 20 131 DyRoBeS C X227WX000 LDI Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help ziel Taper Land Bearing Bearing Data L 0 702 in Da 1 1276 in Cb 0 0015 in 2CbiD 0 00266 Cp 0 0015 in Preload 0 Offset 0 Theta12 100 Thetaz 200 Taper Arc 90 15 Taper Ra 0 565306 LIndercut 0 00151 Taper amp xL 0 658 Load Angle 270 viscosity 1 62E 06 Density 0 03 For Help press F1 Fixed Pad Bearing Dimensional Analysis Comment Taper Land Bearing arc center is specified by 1 Arc center offset 2 Arc center angle from Commonly amp rc Center Angle is the same as the pad leading edge angle ar is located at the mid af the oil groove Coordinates Standard Coordinates 5 1 Load Angle 270 degree Bearing Type E Taper Land m and C Coordinate Angle 8 degree Analysis Option Constant Viscosity Bearing Load 0 71 s APM 2 RPM 2 EBR Units English WO 2 wd 8 Wit 0 Axial Length L 782 finch Rotor Speed RPM Joumal Dia D 1 146 finch Start 75000 End 75000 Ine 1000 Brg Radial Clr 0 0015 finch Lubricant Dynamic Viscosity 1 62e 006 Reyns Number of Pads 3 Density 10 03 Lbm in 3 Bearing Data Far Pad 1 Leading Edge 100 Preload 8 Click here for more On Advanced Features Trailing Edge 200 Offset 8 Save Save s Bun Cancel Adva
6. Elements v0 0 0 125 0 015 45 25 190 350 0 0 0 0 1 25 Far pressure dam bearing with dam in the top pad and central relief track in the lower pad pocket arc pocket arc Relief Track relief rack 7 When the PocketAxL Bearing Axial Length pressure dam becomes a step as shown below BePerf 126 131 Advanced Settings Circumferential Boundary Conditions Reynolds SwiftStieber Reynolds BC is the most realistic C Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel Sommerfeld 2 pi used for educational purposes Dil Flooded English Units Angle degree Length inches Number of Axial Elements Lnhe Theta Theta Preload Offset Pocket rc PocketDepth Elements 0 VK EMO 0 25 EN 10 170 125 0 01 190 350 0 0 0 0 0 0 25 Taper Land Journal Bearing click here for more descriptions on taper land bearings DyRoBeS_BePerf C 222 000 LDI Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Taper Land Bearing Bearing Data 0 782 in Ds 1 1276 Cb 0 0015 in 0 00266 Cp 0 0015 in Preload 0 Offset n Thetal 100 Theta2 200 Taper Are 30 15 Taper Ra 0 565306 LInderCut 0 00151 Taper amp xL 0 658 Load Angle 270 Viscosity 1 62E 06 Density 0 03 For Help press F1 arc c
7. Pivot Angle Lund Convention measured fram A W in X Axis Note that the tilting pad pivot angle is measured from the Negative Load Vector in Lund s Coordinate System 2 Standard Convention The second Cartesian coordinate system X Y Z used to describe the bearing geometry shown in the following figure is a more conventional standard coordinate system and is commonly used by rotor dynamics analysts for the rotor dynamics study X axis is to the right and Y is to the top The circumferential angular coordinate e Is measured from the positive X axis in the direction of shaft rotation The load vector W can be in any direction with respect to the X axis by a specified angle Y A typical 3 lobe bearing using this coordinate system is shown BePerf 10 131 Convention Q measured from X 8 Leading Edge 81 Y W specified hy Ow 5 Trailing Edge Oil Supply Groove The lobe leading and trailing edges for a 20 degree oil supply groove now are Lobe Number Leading Edge Trailing Edge A typical 4 pads tilting pad bearing using this coordinate system is shown W Pivot Angle Convention measured from X w measured from X Pivot Note that the tilting pad pivot angle is measured from the Positive X axis in the Standard Coordinate System The load vector is specified by an angle Ow measured from the X axis Each coordinate system has its own strength and weakness
8. Pocket amp x L Bearing Length Pocket Arc Length 3 Relief Track Relief Track Axial Length Case 1 Relief Track in center Case 2 Relief Track on both side 112 Relief Track 112 Relief Track BePerf 118 131 Fixed Pad Bearing Dimensional Analysis Comment Chapter Example 1 Pressure Dam Bearing with centered Relief Track Coordinates Standard Coordinates Y Load Angle 270 degree Bearing Pressure Dam MultPacket K and Coordinate Angle ERN degree Analysis Option Constant Viscosity Beating Load W 1 x RPM 2 x RPM 2 41E55 Unis Engish wor 1000 wil oo Length L E linch Rotor Speed APM Diameter D P inch Start 1000 End 7000 Inc Brg Radial Clr Cb 0 005 finch 1000 Lubricant Dynamic Viscosity 2 Number of Pads 2 umber of Pads Density 7 Be 005 Lbm in 3 Bearing Data for Pad H 1 10 Preload 8 Click here for Trailing Edge 170 Offset 0 Advanced Features Save Save s Aun Cancel Leading Edge Advanced Settings Circumferential Boundary Conditions ift Sti Ad d Feat Reynolds Swift Stieber Reynolds BC is the most realistic I V Ur es Ok Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect Lance C Sommerfeld 2 pi used for educational purposes Wl tied Number of Axial Elements 8 English Units Angle degree Length inches 4 5 5
9. Load Angle 80 degree K and C Coordinate Angle 0 degree Bearing Load 0 w1 s RPM 42 s RPMH 2 M Ww Wil We 0 Rotor Speeds RPM Additional Speeds Shark 60000 End 150000 Inc 6000 Analysis Soecity Varnables vs Journal APM Ring Speed Calculated from T arque Balance Variables vi Ci 0 0178 Cos 0 05715 Co Ci 3 2107 Ro Fis 1 5440 Estimated Speed 0 3509 BOO00 90000 120000 150000 Insert Aow Delete How PostProcessor 0 05715 0 05715 0 05715 0 05715 Import xls Export sls BePerf 38 131 DyRoBe5 BePerf C 0123 Compressor_end FRB Project Fixed Lobe Tilting Pad Gas Brg Thrust Lubricant Flow Hydrostatic Tools View Help Das Floating Ring Bearing Bearing Data PostProcessor Text Output Tabulated List Oilc 12 02 Eccentricity Ratio Or Cz Ring Eccentricity Ratio Oriel relative Eccentricity Ratio Li 11 28 mm All 3 Eccentricity Ratios Lo 14 mm Oj Or Equilibrium Positions Ds 12 9997 mm Pressure Profiles at C L Di 13 0353 mm Do 20 0711 mm Speed Ratio vs RPM Db 20 1854 mm Power Losses vs RPM Mr 0 0218 kg viscosities vs RPM Ci 0 0178 mm Temperature Rises vs RPM Co 0 05715 mm Clearances vs RPM Coli 3 211 speed Ratio is Calculated Load Angle 90 Floating Ring Bearing Data Options Profile Film Bearing Data Lila 11 28 14 mm Ds
10. The same concept of preload described m the fixed lobe bearings applies to the tilting pad bearings Preload is defined as the fraction of the distance between the pad center of curvature and bearing center to the pad radial clearance OTa G 2 C P BePerf 26 131 Typical preload value for a tiltng pad bearing ranges from 0 15 to 0 75 The Offset also called Pivot Ratio is the fraction of the distance between the leading edge and the pad pivot point to the complete pad arc length The typical pivot offset ranges from 0 50 to 0 65 the pivot point can be anywhere from one half the length of the pad to 65 ofthe pad A pivot ratio of 0 5 is also called centrally pivoted which is suitable for either direction of shaft rotation For better load carrying capacity the pivot point is usually placed further than the midpomt say offset 0 55 An offset factor less than 0 5 increases the diverging film thickness and is not desirable Since pad arc length and pivot offset are used tilting pad bearings instead of leading and trailing edges of the lobe described in fixed lobe bearings the Pivot Angle must be specified in the tilting pad bearing to define the bearing orientation and load vector direction Pivot Angle is the angle from the Negative Load Line for Lund s Coordinate System and from the positive X axis for Standard Coordinate System to the first pad pivot point measured in the direction of shaft rotation Mo
11. 11 1351 Lbm Inertia 1 08877 Lbm in 2 ace Distance fram Pad Center of Curvature to Pad C G 2 85 ir Pad Data Housing D ata Poisson s Ratia 0223 10 29 Elastic Modulus 1 HDD 29000000 LbfZin 2 Radius 512 5 125 TU To select the pad pivot configuration and enter the pad pivot data click the Pad Pivot Data button as shown in the main input screen They are several pivot configurations available n DyRoBeS 1 Neglect Pad Pivot Effect This 1s a conventional configuration which neglects the pad pivot effect The pad is free to tilt without any restrictions 2 Rigid Pivot which is free to tilt with inertia effect In this configuration the pad inertia is included in the pad rotational equation of motion 3 Spherical Pivot it implies the point contact 4 Cylindrical Pivot it implies the line contact 5 General curvatures it has curvatures m both directions 6 Constant stiffness this is used for flexural pad bearings Case 1 Neglect Pad Pivot Effect BePerf 96 131 Pad Pivot Data Pivot Flexibility uil mis Pad 1 1351 Lbm Inertia 1 08877 Lbm in 2 Distance from Pad Center of Curvature to Pad C G 2 585 Pad Data Housing D ata Poisson s Ratio 10 33 10 29 These data are not Elastic Modulus 1 BOUDUOU 29000000 Lbf in 2 necessary when Radius 5 12 3 125 Pad Pivot effect 15 Effective Length 8 in negle cted Axial Radius 8 n in Radi
12. 2Cb D 0 001 0 0025 in T X Preload 0 Offset 0 Thetal 10 Theta2 170 Load Angle 2 0 Viscosity 7E 06 For Help press F1 BePerf 71 131 Fixed Pad Bearing Dimensional Analysis Comment Example from Shapiro amp Colsher Sixth Turbomachinery Symp 1979 English Units Coordinates Standard Coordinates Load Angle degree Bearing Type 2 Two Axial Groove Analysis Constant Viscosity Convert Units English Axial Length L 5 K and C Coordinate Angle degree Bearing Load W w x RPM 2 x RPM 2Z 1E58 WD 20780 WT We 8 Rotor Speeds RPM inch e Additional Speeds Joumal Dia D 5 inch Start 1000 End 10000 Inc 1000 Brg Radial Clr Cb 0 0025 linch Lubricant Dynamic Viscosity 2 006 lt Number of Pads 2 Density 8 Lbm in 3 Bearing Data for Pad 1 Leading Edge 10 Preload 0 Advanced Fetaures Trailing Edge 170 Offset 8 Open Save Save Ag Fixed Pad Bearing Dimensional Analysis Comment Example from Shapiro amp Colsher Sith Turbamachinery Symp 1973 Metric Units Coordinates Standard Coordinates Y Load Angle 270 degree K and C Coordinate Angle 270 degree Bearing Load 10 w1 s RPM 2 RPM 2 IN 1 wo 924341 0200 wa o Rotor Speeds HP M Bearing Type 2 Two Axial Groove Analysis Constant Viscosity Conver
13. Lubricant Mobil DTE Light WG 32 Inlet Temperature 120 degF Heat carried away 80 Yes BePerf 74 131 Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber Reynolds BC is the most realistic t Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only t Sommerfeld 2 pil used for educational purposes English Units Angle degree Length inches Number of amp xial Elements E 28 75 175 0 5494 0 85 195 295 0 5454 0 85 25 318 415 0 5454 0 55 z5 The bearing performance at 48 000 rpm is shown below with turbulence effect CHECKED With 120 F oil inlet temperature the operating and maximum bearing temperatures are 158 and 195 F Fixed Lobe Bearing Dimensional Data Options Profile High Speed Compressor Test Bearing Temperature rise Turbulent Flow Advanced O L 1 25 in D 1 3789 Ch 0 002 in 2Cb D 0 0029 m 0 5454 tilt 0 85 Speed 48000 rpm Load 520 Lbt W LD 301 69 psi Vis 1 2601E 06 Reyns Sb 0 39707 E Cb 0 4369 Att 35 42 deg hmin 1 127 mils Pmax 1162 2 psi 6 76512 hp Oside 1 718 gpm T 120 158 195 degF Stiffness Lbf in Z 590E 05 3 544E 05 3 723 05 9 099E 05 Damping Lbf s in 9 110 01 1 465 01 1 465 01 2 366 02 Critical Journal Mass Lh Tia With Advanced Feature ON the bearing clearance can be easily checked as shown below in top view and side view B
14. The operation is entirely consistent with industrial standard operation in Window environment Help can be obtained at any time by pressing F 17 key The governing equation for pressure distribution in a fluid film journal bearing 15 incompressible Reynolds equation which is derived from the Navier Stokes equation as expressed below The fluid film forces acting on the journal are determined by application of boundary conditions and integration of pressure distribution It is an iterative process until the convergence criterion is satisfied Once the static equilibrium is found the bearing static performance such as bearing eccentricity ratio attitude angle minimum film thickness maximum film pressure frictional power loss oil flow rate etc can be easily determmed Under dynamic conditions the journal is oscillating with small amplitudes around the static equilibrium position The eight bearing dynamic coefficients stiffness and damping are obtained by solving the perturbed pressure equations oh d HE eem GG IG 2 amp 2 Bt where x is in the axial direction and y is in the circumferential direction Gx and Gy called the turbulent flow coefficients are the correctional terms of viscosity caused by the turbulent diffusion 2124 0 0043 Axial direction 12 0 0136 Re Circumferential direction Uh Local Reynolds number For laminar flow Gx G
15. 14 mm Ds 12 8887 mm Dj 13 0353 mm Do 20 0711 mm Db 20 1654 mm Mr 0 0210 kg Ci 0 0178 mm Co 0 05715 mm Co Ci 3 211 Inner Speed Ratio is Calculated Film Load Angle 90 11 Outer Film Ci Di Dsy2 Co Db Doy2 Constant Viscosities specify the viscosities BePerf 36 131 Floating Ring Bearing Comment Compressoe End Bearing Coordinates Standard Coordinates 5 Convert Units Shaft Diameter Ds Bearing Diameter D b Floating Data Mass mr Inner Length Li Outer Length La Inner Diameter Di Outer Diameter Do Hing Shaft Speed A atio 10 35 Metric 12 8337 1201 094 10 0218 11 28 wo 3 0353 20 OF11 mm rari kg mm rnm mm mm Load Angle 80 degree K and Coordinate Angle 8 degree Bearing Load 0 w1 s RPM 42 s RPMH 2 M Ww Wil We 8 Rotor Speeds RPM 1 Additional Speeds Start 60000 End 0000 Inc 6000 Analysis Hing Speed Specified by User Inner Film Viscosity 1 cP aise uter Film iscosity 1 3 cP oise Ci 0 0178 Cos 0 05715 CorCi 3 2107 RorRi 1 5440 Estimated Speed 0 5509 Heat Balance specify the lubricant type inlet temperature supply flow and percentage of heat carry away by lubricant If the supply flow is not known enter zero A sufficient oil flow will be assumed to prevent starvation In general about 50 80 of the heat gene
16. Close The temperature for the inner oil film is normally higher than that of the outer oil film therefore it has a smaller viscosity than that of outer film Floating Ring Bearing Data Options Profile Film Bearing Data Li Lo 0 4 0 5 in 05 01 0 4332 0 434 Do Db 0 75 0 7525 in Ci Co 0 0004 0 00125 in Co Ci 3 125 Mr 0 037 Lbm Mui 1E 06 Reyns 2E 06 Reyns Speed Ratio 0 2 Load 0 5 Lb Rotor RPM 120000 rpm ej Ci Co 0 0039 hmin 0 40 1 24 mils Pmax 5 34 2 50 psi Loss 1 7198 hp Kixx xy 1 12 05 1 39 06 Lbf in KiyX yy 1 99E 06 1 10E 05 Lbf in Turbocharger Floating Ring Example page 279 Cixx xy 1 84E 02 1 48E 01 Lbf s in CiyX yy 1 48E 01 2 64E 02 Lbf s in Koxx xy 3 62 03 6 04E 04 Lbf in Koyx yy 8 19 04 2 31E 03 Lbf in Coxx xy 4 80 01 2 56E 00 Lbf s in Coyx yy 2 56E 00 6 52E 01 Lbf s in BePerf 101 131 Floating Ring Bearing Output C for DyRoBeS Rotor Current Units K C Lbf s in output current Conversion Factor Cancel Output units For and ECOLE Lbf in Other H s m M s mm Output filename Click left buttons to Enter the file name and C data Total Impedance CAMpPoldersOvRobes SE ample E amples Turbachargerz brg Inner Film C MuFoldersOuRobeS SE xample Turbacharger Inner b
17. If you wish to install and run on more than one computer site license agreement is required You may not transfer the program and license to another party All intellectual property rights trade secrets and other proprietary material are owned by Eigen Technologies Inc ETT This license is effective until terminated You may terminate it at any time by destroying the programs and related materials together with all copies modifications and merged portions in any form This license will also termmate immediately if you fail to comply with any provision of this agreement You agree upon such termination to destroy the programs and related materials together with all copies modifications and merged portions in any form Eigen Technologies Inc warrants the media on which the programs are furnished to be free from defects in material and workmanship under normal use for a period of 60 days from the date delivery to you ETI will replace any media not meeting the foregoing warranty and which is returned to The foregoing warranty does not extend to any media which has been damaged as a result of accident misuse or abuse Limits of Liability and Disclaimer of Warranty The author and publisher have used best efforts in preparing this manual the program and data on the electronic media accompanying this manual These efforts include the development research and verification of the theories and programs But due to the complex
18. Load Angle 270 degree Bearing Type E Pressure D am Step Pockets K and C Coordinate Angle 0 degree Analysis Option Constant Viscosity oF Bearing Load W0 w x RPM Ww x RPM 2 4E58 Convert Units English Ww 3000 Ww 8 Wie 0 Axial Length L inch Rotor Speeds RPM Additional Speeds Joumal Dia D inch Start 7000 End 7000 Inc 1000 Brg Radial Clr 10 005 linch Lubricant Dynamic Viscosity 2e 006 Feyns Number of Pads 2 Density 10 03 Lbm in 3 Bearing Data for Pad 1 Leading Edge 10 Preload WS Trailing Edge Offset 8 Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber Reynold BC ts the most realistic t Gumbel half Sommerteld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel t Sommerfeld 2 pi used for educational purposes Dil Flooded English Units Angle degree Length inches Number of Axial Elements PocketDepth Pocket xL 10 170 D D 125 0 015 4 5 D 25 130 350 0 0 0 0 0 1 25 The bearing performance and pressure distribution are shown below BePerf 78 131 Ell Fixed Lobe Bearing Dimensional Data Options Profile Pressure Dam Bearing with center relief track 6 in D 6 in Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 Speed 7000 rpm Load 3000 Lbf W LD 83 3333 psi Vis 2E 06 Reyns Sb 1 008 E Ch 0 6049 Att 56 64 deg hmin 1 975
19. One 1s the Lund coordinate system where the load vector is collinear with the X axis One 1s the standard coordinate system where X axis is to the right and Y axis is to the top The load vector direction is specified by an angle Click here to see more description on coordinate systems Coordinates tere Lund Coordinates X Ww Standard Coordinates psr Bearing Type Several bearing types are provided in the list for selection Ifthe bearing under study is not in the list select the General Fixed Profile type and input the bearing geometrical data This selection has been made for the convenience ofthe user since it allows the program to supply the user with typical defaults in Number of Pads Leading and Trailing Edges Preload and Offset You are free to make your changes on these default data to suit for your need Some special bearing types are also included such as pressure dam bearings step bearings multi pockets bearings and taper land bearings etc These bearings have discontinuity in the bearing clearance and require additional which are under the Advanced Features button Bearing Type 223 Plain Cylindrical Journal Partial Arc Two Axial Groove Elliptical Lemon Bore Offset Halves 5 Three Lobe Four Lobe General Multi Lobes Pressure D amStep Pockets 11 General Miulti amp res Analysis Option The analysis can be performed m either Constant Vis
20. Pr gpm Position it Lae bil bit aland Depth Ped Pump de E Capillary 15 2828 Capillary 15 2828 Capillary 15 2828 15 2828 Capillary 15 2828 Capillary 15 2828 BePerf 52 131 Hydrostatic Hybrid Journal Bearings Comment Hydrostatic Journal Test Howe Orifice Restrictor Coordinate System Standard Coordinates 4 7 theta from pos Analysis Isothermal Convert Units English in Lbf psi degF Reyns Lbm in 3 gpm rpm Jaurnal Dia D 3 Axial Length L Viscosity 5E 06 Density 10 03 Pamb 0 Brg Radial Clr Cb oon 2 an Note Pad data required only when preload exists Ma of Recesses Ma of Pads 0 Pad Data No of Pumps i Pump Data No of Loads 1 Load Data Recess Pocket Data Filin the data if all the recesses are identical and cyclic symmetric then all other recess data will be duplicated from the 1st recess 1 and 1 1 are the adjacent recess numbers for the Hh recess o indicates the slot if no axial slot then for the 1st recess is NA Position Arc bi 1 67 degree a Land Depth de do lc in Pr psi Not Postion it abend Denth Pad Pumo Cd Hydrostatic Hybrid Journal Bearings Orifice Orifice Orifice Orifice Orifice Orifice Comment Hydrostatic Journal Test Rowe Specified Flow Coordinate
21. X Preload m E E P Typical Preload value for a fixed lobe bearing ranges from 0 4 to 0 75 Offset or Tilt BePerf 23 131 6 41 2 SO 15 41 7 where 9 18 the angle from the reference axis to the line connecting the bearing center and the pad center of curvature At this point the bearing has minimum clearance for a centered shaft and the lobe arc intersects with bearing base circle Typical Offset value for a fixed lobe bearing ranges from 0 5 to 1 0 Coefficients Coordinate le The coordinate system x y z used to describe the bearing dynamic coefficients stiffness and damping coefficients can be different from the X Y Z coordinate system used to define the bearing geometry The Coefficients Coordinate Angle is the angle measured from the X axis For Lund Coordinate System 0 degree 1 x axis is in the loading direction and 90 degrees 1 e negative y axis is in the loading direction are commonly used See also Coordinate Systems Fixed Lobe Bearing Geometry Fixed Lobe Dimensional Analysis Nomenclature Non Dimensional Parameters Coefficients Coordinate Angle BePerf 24 131 Tilting Pad Journal Bearing Table of Contents Tilting Pad Journal Bearing For high speed and lightly loaded rotating machines the bearings with fixed geometry are prone to self excited vibration Tilting pad pivoted pad journal bearings are widely used in high speed machiner
22. and relief track are introduced these types of bearings The following figures are shown for a typical 2 lobes pressure dam bearing However this option allows you to have as many lobes as you like and each lobe can have preload offset pressure pocket or relief track The following design rules for the pressure dam bearings have been suggested by Dr John Nicholas leading researcher in pressure dam bearings 1 The optimum Sommerfeld number range for designing a pressure dam bearing to increase stability is S gt 2 0 2 The optimum Clearance Ratio is around 3 0 A slightly larger clearance ratio 3 0 6 0 is recommended to avoid the sudden drop in load capacity for clearance ratios below 3 0 3 Steps should be located at about 75 ofthe total arc length ofthe pad The optimum step location for stability is between 125 and 160 degrees for 2 lobes bearings depending upon the Sommerfeld number A reasonable compromise value is 140 degrees 4 Relief track m the loaded pad should be avoided due to the high operating eccentricity ratio 5 Pocket axial length should be 65 to 70 of the total axial bearing length To use these types of bearings the Advanced Features must be checked in the input The positive relief track axial length indicates that the relief track 15 in the center and the negative relief track axial length indicates that the relief track is on both sides as shown below Pressure Packet eu i Pocket
23. 0 90 15 0 565306 0 0015 340 0 658 0 0 25 Taper Land Bearing Parameters Knawn Parameters Arc Length Am Radius Arc Length Cancel Undercut Arc Length Center Offset known Data Arc Center Angle Pad Leading Angle Pad Trailing Angle Bearing Radius Rib LIndercut Arc Radius Center Offset Arc Radius Center Offset LIndercut Needs to know 2 data Undercut 0 001606 Arc Length FAN Arc Radius 0 565306 Center Offset ooms 25 25 For Taper Land Bearing the undercut and taper length are normally specified in the design process however the arc center and arc radius are typically specified in the manufacturing drawings A Tools button is provided for this conversion BePerf 128 131 Advanced Settings Circumferential Boundary Conditions f Reynolds Swift Stieber The Reynolds BC is the most realistic Advanced Features Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect t Sommerfeld 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements 0 0 100 200 0 565306 0 0025 100 0 655 220 320 0 0 90 0 565306 0 0025 220 0 658 440 0 0 90 0 565306 0 0025 340 0 655 Taper Land Bearing Parameters Known Parameters Arc Length 9 Undercut Arc Length Center Offset Arc Radius LIndercut Arc Radius Center Offset Known Data Arc
24. 10 03 Lbm in 3 Leading Edge Freload 0 Advanced Fetaures 1 Trailing Edge 170 Offset 8 Open Save Save Ag Aun Close Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber The Reynolds BC ts the mast realistic t Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only t Sommerfeld 2 pil used for educational purposes English Units Angle degree Length inches Number of Axial Elements 8 10 170 0 0 125 0 015 E 0 190 350 0 0 0 0 Ell Fixed Lobe Bearing Dimensional Data Options Profile 0 Step Bearing modelled with Type 8 Pressure Dam Bearing without side dams L 6 in D 6 in Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 Speed 7000 rpm Load 3000 Lbf W LD 83 3333 psi Vis 2E 06 Reyns Sb 1 008 E Ch 0 1860 Att 97 07 deg hmin 4 113 mils Pmax 240 526 psi Hp 32 5517 hp Oside 25 482 gpm Stiffness Lbf in 1 433 06 1 250 06 8 025 06 1 371 06 Damping Lbf s in 4 535 03 1 831E403 1 832 03 1 262 04 Critical Journal Mass Lh 3280 8 BePerf 88 131 It can also be modeled with Type 9 Taper Land Bearing as illustrated below The results are identical in two cases L3 DyRoBeS BePerf C MyFolder DyRoBeS Examples Bre Step Brg Type 9 LDI Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help Step Bearing modelled with Type 9
25. 5000 Required for Flow and Power Loss Analyses Results Viscosity 34 473785 cFoize Stiffness 2 4824E 05 Mmm Constant Flow Restrictor Total Flow Rate 0 20016 Liter Min Pumping Loss Friction Loss 0 00345 kw O12 kw Speed rpm 1000 Used in Friction Loss Hecess Depth 4 BePerf 58 131 Hydrostatic Journal Bearing Design Tool Convert Units Metric mm deg MPa of Recesses 4 Axial Slot 0 degree Journal Dia D 120 Circumferential land b 20 05 degree Avial Length L 100 Axial side land width 18 0 120 Rec 69 95 deg 2T heta 90 00 deg b 21 00 mm Brg Radial Clr Cb 01 Supply Pressure Ps 1 2 Hestrictar Capillary Tube Pressure Pr 0 60165 0 5014 Required Far Flow and Power Loss Analyses r Results Viscosity 85 cPaise Stiffness 82196 M mm de 4 Le 0 035752 Min de 0 8942 mm Total Flow Rate 1 4825 Liter Min Lc 58 dc 1 p Lc dc 48 33 Pumping Lass Friction Loss 0 0296 EM b 45 kw Speed rpm 3000 Used in Friction Loss Recess Depth 3 BePerf 59 131 Lubricant Table of Contents Lubricant An accurate lubricant dynamic viscosity is essential to the calculation of bearing performance The basic properties of a number of commonly used lubricants are collected and stored in a library User can always add new lubricants into the library or edit the existing lubricants by se
26. 9091 Cb 0 0029 2Ch D 0 00268 m 0 3 Offset 0 6 Arc 72 PivAng 27 180 160 140 i a co ce E i 120 30000 32500 35000 37500 40000 Rotor Speed rpm BePerf 94 131 L Tilting Pad Bearing Dimensional Data Options Profile 4 Pads TPJ Compressor Applicatin L D 0 9091 0 0029 2Cb D 0 00268 m 0 3 Offset 0 6 Arcs 72 PivAng 27 Speed 35000 rpm Load 1470 Lbf W LD 344 861 psi PN E Cb 0 4555 p Att 0 00 deg hmin 1 272 mils Pmax 1278 35 psi Hp 17 1661 hp Oside 4 221 gpm Qsup 5 gpm T 110 144 176 degF Um Stiffness Lbf in j oe UN 1 546E 06 0 000 00 gt 0 000E 00 1 546E 06 QU Damping Lbf s in 4 253E 02 0 000E 00 0 000E 00 4 253 02 Critical Journal Mass Lb Stable A 6 gt NS jus et AUN SS me we MI MM de For 4 pads and load between pivots the bearing stiffness and damping are identical in both X and Y directions This implies that the bearing properties are isotropic Example 8 4 Pads Tilting Pad Bearing with Pivot Flexibility In this example the pad pivot flexibility is studied For big bearings with larger pads the pad effect may need to be included m the analysis A tilting pad bearing used in the generator application is employed in this example The bearing under study has spherical pivots In this example several different pad pivot con
27. B LDI Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help Step Bearing modelled with Type 8 Pressure Dam Bearing without side dams Bearing Data L 6in Ds 6in Cb 0 005 in 0 00167 Cp 0 005 in Preload 0 Offset 0 Theta1 10 Theta 2 170 Pocket Arc 125 Depth 0 015 Width 6 Load Angle 270 Viscosity 2E 06 Reyns Density 0 03 Lhmin 3 For Help press F1 Fixed Lobe Bearing Dimensional Data Options Step Bearing modelled with Type 8 Pressure Dam Bearing L 6 in D Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 Clearance Distribution Max C 0 02000 Min C 0 00504 3D FEA Mesh Data BePerf 87 131 Fixed Pad Bearing Dimensional Analysis Comment Step Bearing modelled with Type 8 Pressure Dam Bearing without side dams Load Angle 270 degree Bearing Type sure Dam Step Pockets and C Coordinate Angle 0 degree x RPM 2 RPH 2 1E55 Convert Units English wil 3000 Wil 0 Whe 0 Coordinates Standard Coordinates Analysis Constant Viscosity Bearing Load WO Asial Length L inch Dg Rotor Speeds RPM Joumal Dia D 6 inch Start 17000 End 7000 Inc 1000 Brg Radial Clr Cb 0 005 linch Number of Pads 2 Bearing Data for Pad 1 Lubricant Dynamic Viscosity 2e 006 lt Additional Speeds Density
28. Between Pivots Cis herfor Pivot Type Spherical Point Contact Pad Pivnat Data Pivot Type Spherical Pivot Point Contact Mew Save Save As Bun Close Comment This is used to describe the bearing under study Coordinates BePerf 28 131 Two coordinate systems can be used to describe the bearing geometry One is Lund coordinate system where the load vector is collinear with the X axis One 1s standard coordinate system where X axis is to the right and Y axis is to the top The load vector direction is specified by an angle Click here to see more description on coordinate systems Coordinates TR T Lund Coordinates X Ww Standard Coordinates m Load Angle The load angle is needed and shown in the input screen only when the Standard Coordinate system is selected When Lund coordinate system is selected the load vector is the same as the X axis and it is not displayed on the screen Analysis Option The analysis can be performed m either Constant Viscosity or Heat Balance option Depending upon the analysis type the input dialog box changes accordingly For Heat Balance option user must select a lubricant from the list input the oil inlet temperature and estimate the percentage heat carried away by oil The operating and maximum film temperatures will be calculated based on heat balance method In addition the oil flow rate can be specified for heat balance calcul
29. Journal Mass 14 27 es AUT See a z wa BePerf 120 131 Fixed Lobe Bearing Dimensional Data Options Profile Chapter Example 1 Pressure Dam Bearing with Relief Track on both sides L 6 in D 6 in Cb 0 005 in preload offset 0 Z rpm 000 E Cb 0 4125 Pressure 343 57 3D Pressure Profile Note that this bearing type can be de generated into a standard multt lobe bearing if PocketArc PocketDepth PocketAxL and ReliefAxL zero as shown below Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber The Reynolds i the most realistic t Gumbel half Sommerteld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel Sommerfeld 2 pil used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements 1 90 190 0 95 210 0 95 430 0 95 DyRoBeS_BePerf 122213 8 101 Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Ol 3 Lobe Bearing Modelled with Type 8 Pressure dam Bearing Data Y L 1 25 in Ds 1 375 in Cb 0 00175 in 2C b D 0 00255 Cp 0 004375 in Preload 0 6 Offset 0 95 90 Thetaz 190 Load Angle 260 Wiscosity 1 5E 06 For Help press F1 Also if PocketAxL Bearing Axial Length then the pocket has open ends and
30. Lund Coordinate System 0 degree 1e x axis is in the loading direction and 90 degrees 1 negative y axis is in the loading direction are commonly used Bearing Load W The bearing load is expressed as a second order polynomial function ofrotor speed rpm This provides an opportunity to approximate the variation in load with speed W W W x W rpm Rotor Speed rpm Start End and Increment Speeds specify a list of speeds at which calculations are to be performed Additional Speeds Ifthe Additional Speeds is checked additional speeds can be entered in additional to the speeds given by the Start End and Increment Speeds BePerf 18 131 Lubricant This input 15 for Heat Balance analysis option only Ifthe lubricant used in the analysis 15 not in the list you can enter it from the Edit Lubricant Library under the Lubricant menu Inlet Temperature This input is for Heat Balance analysis option The lubricant inlet supply temperature Percent Heat carried Away by Lubricant This input is for Heat Balance analysis option Default is 80 Typical value for fixed lobe bearings is between 80 90 The heat generated in the bearing needs to be removed by lubricant and other means Majority of the heat is removed by lubricant Lubricant Dynamic Viscosity This input 15 for Constant Viscosity analysis option Lubricant Density This input 15 for Constant Viscosity analysis option when the Turbulence
31. Pivot Flexibility NR Rc RC BePerf 32 131 Pad Pivot Data Pivot Flexibility o Be Pad Mass Lbm Inertia 8 Lbm in Close Distance fram Pad Center of Curvature to Pad C G 8 Pad Data Housing D ata Poisson s Ratio 10 33 10 29 Elastic Modulus 29000000 Lbf in 2 Radius BE 5 125 in Pad Pivot Data Pivot Flesibility General Curvature Pad Mass 8 Lbm Inertia 8 Lbm in 2 Distance fram Pad Center af Curvature to Pad C G 8 iri Pad Data Housing Data Poisson s Ratio 0 22 0 29 Elastic Modulus 1 29000000 2 veins BE 5 125 Note Negative Axial A adius 51 2 5 125 in Pad Pivot Data Pivot Flexibility Constant Stiffness Pad Mass 0 1 Lbm Inertia 0 001 Lbm in 2 Cees Distance fram Pad Center of Curvature to Pad C G 25 5 Radial Stiffness i Lbf in Tangential Stiffness 8 Rotational Stiffness 2500 Lbf irv rad See also Coordinate Systems Tiltng Pad Bearing Geometry Tilting Pad Non Dimensional Analysis Fixed Lobe Bearing Geometry Nomenclature Units Lubricant Examples Coefficients Coordinate Angle BePerf 33 131 Tilting Pad Non Dimensional Analysis Table of Contents Tilting Pad Bearing Non Dimensional Analysis In the non dimensional tilting pad bearing analysis the effects of p
32. System Standard Coordinates 4 7 theta from pag S Analysis isothermal Convert Unite English in Lbf psi degF Reyns Lbm in 3 gpm rpm Journal D 3 Length L Viscosity 5E 06 Density 10 03 Pamb n Brg Radial Clr Cb 10 007 2 Note Pad data required only when preload exists of Recesses E Re 3 of Pads 8 Pad Data Ma of Pumps i Pump Data No of Loads 1 Load Data Save Ag Cancel i m and 1 1 are the adjacent recess numbers for the i th recess E the slot if no axial slot then i1 for the 1st recess NF Position Arc 6 1 b degree Land Depth de do lc in Pr gpm Gr Specified Specified Specified Specified 0 008813 0 008813 0 008813 0 008613 0 008613 0 008913 BePerf 53 131 DyRoBeS_BePerf C 1610 Hybrid_Dowson HSJ Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Hydrostatic Tools wiew Help Hydrostatic Journal Test PP 425 dx Bearing Data L 100 mm Ds 120 mm Cb 0 1 mm 2C b D 0 0017 151 Recess Ang U Recess Arc 69 95 bfi 1 20 05 bir 20 05 2 Theta 90 a 10 mm Depth 3 mm Ps 1 2 MPa Restrictor Capillary Viscosity a5 cP Density 0 85 g CE For Help press F1 Hydrostatic Hybrid Journal Bearings E Comment Hydrostatic Journal Test PP 425 Coordinate System Standard Coordinates 4 7 the
33. another recess Assuming N is the total recess numbers For the first recess 1 I 1 will be either N cyclic symmetric and not slot or 0 if slot exists For the last recess IN will be either 1 cyclic symmetric and no slot or 0 if slot exists b I 1 is the inter recess land between I and 1 1 b I 1 is the inter recess land between I and 1 1 a is the axial land width per side Pad number is needed only if bearing is preloaded and or tilting pad bearing Each pad is separately by the oil slot Three different restrictor types can be used in this program They are Capillary Orifice and constant flow Many examples are provided for reference BePerf 50 131 DyRoBeS BePerf C 41610 Hybrid_RBTS HSJ Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubriceant Flow Hydrostatic Tools wiew Help Bearing Data L 26 in Ds 90 in Ch 0 02 tn 2Ch D 0 0004 Recess Ang 236 304 Recess Arc 32 32 bfi 1 10 36 b i 1 36 10 2 Theta 55 55 slot 240 00 0 00 9 Gin Depth 0 1 0 1 in Fs 100 psi Restrictor Gr Viscosity 2 06 Reyns For Help press F1 Hydrostatic Hybrid Journal Bearings iem Data Comment Example Coal Pulverizer Flow is specified per Recess Supply Pressure 1 the pressure before the Hestrickar Coordinate 5 ystem Standard Coordinates ev theta from x pos Xx Flow
34. display the opening screen of Help From the opening screen you can jump to step by step instructions for using DyRoBeS and various types of reference information Once you open Help you can click the Contents button to open the DyRoBeSO User s Manual The help offers you an Index to topics on which you can get help You can also use Find to find any particular word that you like to get help You can press lt F1 gt at any time to get help Use the Context Help command to obtain help on some portion of DyRoBeS When you choose the Toolbar s Context Help button the mouse pointer will change to an arrow and question mark Then click somewhere in the DyRoBeS window such as another Toolbar button The Help topic will be shown for the item you clicked When you are in the help screen you can click on any GREEN font topics this will lead you to that topic BePerf 6 131 Table of Contents Project A Project is also called a File or a Document which contains the bearing geometric and operating data All the options under the Project are self explanatory You can start with a new file open an existing file or close a file These functions are also available in the analysis input dialog box Fight most recently used files are listed for quick selection Since the program can perform fixed lobe and tilting pad dimensional and non dimensional analyses floating ring bearing gas bearing and thrust bearing analyses Seve
35. is ignored DK Lp Hs Pad radial clearance Pad radius Shaft radius Cb Rb Hs radial clearance Brg radius Shaft radius Preload m Ep Cb Lp 1 Loaded Pad 5 Generally Reference Pad shall be the loaded pad Reference Pad 5 0 005 In Cb Cp 1 m 0 00350 0 00250 0 00550 0 00500 0 00500 Number of Pads Npad Number of pads lobes supported by pivots Pad Arc Length degrees cB E Typical values are 55 60 degrees for 5 pads bearings and 70 75 degrees for 4 pads bearings Pad Pivot Offset Tp tQ where is the angle from the leading edge of the pad to the pivot point in the direction of shaft rotation Typical pivot offset value ranges from 0 5 to 0 65 Load Vector and Pivot Angle The bearing can be orientated such that the load vector is directed onto the pivot between the pivots or at any arbitrarily specified pivot angle Most tilting pad bearings are designed such that the pivots are symmetrical with respect to the load vector i e the load is directed onto a pad pivot or between two pivots When you select either Load on Pivot or Load between Pivots then you do not need to mput the Pivot Angle 1t will not be shown in the screen either The Pivot Angle will be calculated and updated automatically for you m these two cases Pivot angle is the angle in degrees measured from the Negative Load Line for Lund s Coordinate System and measure
36. it becomes a step bearing as shown below BePerf 121 131 Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber Reynolds BC is the most realistic Iv Advanced Features f Gumbel half Sommerteld Gumbel and Sommerfeld BCs only Turbulence Effect Cancel t Sommerfeld 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Elements 8 0 0 25 10 170 125 0 01 190 350 0 0 0 0 0 0 25 Step Bearing PocketAxL Bearing Axial Length DyRoBeS BePerf C 222 Step Brg B LDI Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow wiew Help Pressure Dam Bearing without relief track Hearing Data Ds Bin Co 0 005 in 2CbiD 0 00167 0 005 in Preload 0 Offset 0 Thetal 10 Thetaz 170 Pocket Arc 125 Depth 0 01 Width 6 Load Angle 270 Viscosity 2E 06 Density 0 03 For Help press F1 See also Coordinate Systems Fixed Lobe Bearing Geometry and Examples BePerf 122 131 Taper Land Bearing Table of Contents Taper Land Bearings To use the Taper Land Bearing the Advanced Features must be checked m the input The taper land journal bearing is commonly used in locomotive turbocharger application The leading convergent area of the lobe is cut by a taper arc to increase the convergent area Normally t
37. mils Pmax 605 61 psi 38 8325 hp 4 12 277 gpm Stiffness Lbf in 3 359E 06 1 753E 05 5 938 06 4 685 06 Damping Lbf s in 4 733E 03 4 435 03 AASSE 03 1 139E 404 Critical Journal Mass Lb 11643 Ell Fixed Lobe Bearing Dimensional Data Options Profile Pressure Dam Bearing with center relief track L 6 in D Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 rpm 7000 E Cb 0 6049 Max Pressure 605 63 3D Pressure Profile Theta Note that the central relief track can significantly lower the bearing load carrying capability Therefore caution must be taken when using the relief track When the ReliefAxL is negative value the relief track will be on both sides instead of at the center The configuration with side relief track provides a better loading carrying capability than the central relief track The same example with side relief track 1s illustrated below BePerf 79 131 Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber Reynolds BC is the most realistic Iv Advanced Features f Gumbel half Sommerteld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel t Sommerfeld 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements 8 0 0 45 0 25 10 170 125 0 015 190 350 0 0 0 0 0 Pl jd 25 0 5 at each side DyRoBeS BePerf C M
38. nature of this type of software the author and publisher make no expressed or implied warranty of any kind with regard to these programs nor the supplemental documentation in this manual including but not limited to their accuracy effectiveness or fitness for a particular purpose In no event shall the author publisher or program distributors be liable for errors contained herein or for any incidental or consequential damages in connection with or arising out of the furnishing performance or use of any of these materials The information provided by these programs is based upon mathematical assumptions that may or may not hold true in a particular case Therefore the user assumes all of the risks in acting on or interpreting any ofthe program results BePerf 2 131 Introduction Table of Contents Introduction DyRoBeSO BePerf computer program has been developed to analyze the Bearing steady state and dynamic Performance of fixed lobe flexural pad and tilting pad hydrodynamic journal bearings and gas lubricated journal bearings based on the Finite Element Method FEM In addition to journal bearing analysis the program also performs thrust bearing analysis lubricant properties analysis and oil flow calculation The acronym DyRoBeS denotes Dynamics of Rotor Bearing Systems The program contains extensive modeling analysis and post processing capabilities This Window based software is very user friendly and easy to use
39. of expansion BePerf 60 131 If you do not know the coefficient of expansion then enter zero in the input The program will estimate it based on the specific gravity and data table provided in the Handbook of Lubrication Coefficients for specific heat The specific heat is a function of temperature and specific gravity If you do not know the coefficients for specific heat then enter zeros The program will estimate them based on the data provided in the Publication No 97 from Bureau of Standards Lubricant Data Sheet Lubricant Typical 150 YG 32 Title Typical 150 WG 32 Specific Gravity c3 60 F 15 5 097 Viscosity cSt Ei Temperature deg 104 Viscosity cSt 5 Temperature deg F 212 Pour Point deg 15 Flash Paint deg 400 Coeff of Expansion 1 deg F 0 00043 Specific Heat Btu Lbm F 1 2 2 041 b Cpl 0 00048 Cp 0 Cp 0 Lubricant Properties This function tabulates the lubricant properties viscosity density specific heat for a range of temperatures specified in the dialog box The results are displayed immediately on the screen You can view print and save the file Lubricant Properties Table Lubricant Amokon ISO VG 32 Operating Temperatures deg F Starting 50 Ending 1250 Incremental 10 BePerf 61 131 1 Notepad File Edt Search Help DyRoBeS Lubricant
40. press F1 BePerf 83 131 Ell Fixed Lobe Bearing Dimensional Data Options Taper Land Bearing Locomotive Turbocharger Application L 1 3 in D 1 8898 in 0 003 in 2Cbh D 0 00317 m 0 tilt 0 Clearance Distribution Max C 0 007928 Min C 0 00700 3D FEA Mesh Data The input parameters for the tapered land bearing are shown below Since the clearance is not continuous due to the side dams Advanced Feature has to be ON For the manufacturing drawing the arc radius and arc center location r and theta are normally specified In the design process the undercut and taper arc angle length are normally specified For this purpose a TOOLS button is provided mn this dialog box It allows the program users to specified any two parameters among the undercut u arc length Arc theta arc radius Ra and arc center offset r to calculate the other two unknowns Fixed Pad Bearing Dimensional Analysis Comment Taper Land Bearing Locomotive Turbocharger Application Coordinates Standard Coordinates s r Load Angle 270 degree Bearing Type SEM Paper Lar K and C Coordinate Angle 0 degree Analysis Constant Viscosity Bearing Load Wl 5 1 x RPM We x RPM 2 68 Convert Unis English Wi 20 Ww 8 2 Axial Length L 1 3 finch Rotor Speeds RPM Additional Speeds Joumal Dia D 1 8838 inch Start 25 000 End 25000 Inc 1000 Brg Radial Clr 10
41. primary functions 1 Fixed Lobe Journal Bearing 2 Tiltng Pad Journal Bearing 3 Floating Ring Bearing 4 Gas Journal Bearing 5 Thrust Bearing 6 Hydrostatic Bearing 7 Lubricant 8 Flow Calculation See also DyRoBeSO Rotor BePerf 4 131 Getting Started Table of Contents Getting Started When you start the program the following Main Frame Window appears on the screen There are many ways to invoke a program You can refer the Window Help manual for details Depending upon your Window setup and the time when you execute the DyRoBeSO your screen may possibly look different The entire user s manual can be viewed by click on the Help topics under the Help menu Or you can press lt F1 gt anywhere and anytime to get help In the help you can click on any Green font topic to lead you to that topic Click on How to Use Help now to see how it works You can also use the Context Help command to obtain help some portion of DyRoBeSO BePerf When you choose the Toolbar s Context Help button the mouse pointer will change to an arrow and question mark Then click somewhere in the DyRoBeSO BePerf window such as another Toolbar button The Help topic will be shown for the item you clicked DyRoBeS BePerf Untitled Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help For Help press F1 BePerf 5 131 How to Use Help Table of Contents Help Topics Use this command to
42. rad N m rad M m rad U 112884B Lbf in rad Gravity g 388 088 ins 9 8066 m s O C F 32 5 9 H C QF 32 5 8 02 Viscosity Reyn centiP oise 757 EUG Reyn Lbf s in cP 1 0EU3 Pa s cP g cc cSt mm s m inour 0 2271 gpm kWatt 0 7457 hp 2 Table of Contents BePerf 107 131 References Table of Contents References Bureau of Standards Miscellaneous Publication of the Bureau of Standards No 97 Specific Heats of Lubricating Oils Cameron A 1966 The Principles of Lubrication Wiley New York Chen W J and Gunter W J 2005 Introduction to Dynamics of Rotor Bearing Systems Trafford Publishing Chen W J 1995 Bearing Dynamic Coefficients of Flexible Pad Journal Bearings STLE Tribology Transactionn Vol 38 pp 253 260 Hamrock B J 1991 Fundamentals of Fluid Film Lubrication NASA RP 1255 pp 549 Jones G J and Martin F A 1978 Geometry Effects in Tilting Pad Journal Bearings ASLE Trans Klaus E E and Tewksbury J 1983 Liquid Lubricants CRC Handbook of Lubrication Vol pp 229 240 Lund J W 1964 Spring and Damping Coefficients for the Tilting Pad Journal Bearing ASLE Trans Vol 7 No 4 Lund J W and Thomsen K K 1978 A Calculation Method and Data for the Dynamic Coefficients of Oil Lubricated Journal Bearings ASME Publication Topics in Fluid Film Bearing and Rotor Bearing System Design and Opti
43. than and equal to the side leakage 1 e Qsupplied lt Qside the specified flow rate will be used as the effective flow rate Note this starvation will result in overheated bearing and is not desirable Osupplied lt Qside gt Qeffective Qsupplied 1 When the specified oil flow rate is greater than the side leakage 1 e Qsupplied gt Qside the effective flow rate is estimated using the empirical expression Integration factor is a parameter used m the flow integration Typical value for this Q integration factor from many test data shows that BePerf 31 131 the value is between 0 2 and 0 4 with an average of 0 25 to 0 3 This parameter heavily depends on the bearing construction pad shape and design the orifice configuration ways of supply oil ways of drain oil etc Q Integration Factor Typical value for this integration factor from many test data shows that the value is between 0 2 and 0 4 with an average of 0 25 to 0 3 Lubricant Dynamic Viscosity This input is for Constant Viscosity analysis option Pad Pivot Data Several types of Pad Pivot configurations are available in this program When you click on Pad Pivot Data Button a new dialog box will pop up as shown below The input parameters are based on the type of Pivot Flexibility selection The dialog box will change itself depending upon the selection Only the parameters required will appear in the dialog box For Spherical Pivot and Cylind
44. 0 10 170 125 0 015 150 350 0 0 D D 0 50 Positive Central Relief Megative Side Relief Ell Fixed Lobe Bearing Dimensional Data Options Profile Chapter 6 Example 1 Pressure Dam Bearing with centered Relief Track L 6 in DS 6 in Cb 0 005 in preload 0 offset 0 speed 00 rpm Load 1000 L hf WILD 27 7778 psi Vis 2 06 Reyns ob 2 592 E Cb 0 6172 56 03 deg hmin 1 814 mils Pmax 366 165 psi 18 0708 hp stiffness 2 1 bEHIB 2 918 06 TT SN 3 20609E 14 1 670E 06 NUT Damping iLbf s in il 2 713E 3 2 15E HS 2 979E 3 Critical Journal Mass 15 38 BePerf 119 131 Fixed Lobe Bearing Dimensional Data Options Profile Chapter Example 1 Pressure Dam Bearing with centered Relief Track L D 6 in Cb 0 005 in preload offset 0 rpm 000 E Ch 0 61772 Max Pressure 366 16 3D Pressure Profile Fixed Lobe Bearing Dimensional Data Kef Options Profile Chapter 6 Example 1 Pressure Dam Bearing with Relief Track on both sides L 6 in DS 6 in Cb 0 005 in preload 0 offset speed B000 rpm Load 1000 Lbt WILD 27 7778 psi Vis 2 06 Reyns sb 2582 E Cb 0 4125 Att 69 70 deg hmin 2 937 mils Pmax 343 57 psi Hp 15 8343 hp Stifness B3E4Ub A795E 05 1 655E 05 Damping iLbf s in Bg 14bE I3 2 BS4E 05 2638EH S 3 745E 05 Critical
45. 00 100000 120000 140000 160000 Rotor Speed rom W Floating Ring Bearing Data Options m 2 m _ a m i 1 Test Bearing Heat Balance Analysis Speed Ratio is Calculated Inner Film Outer Film a en ee ee ae 40000 60000 B0000 100000 120000 140000 160000 Rotor Speed rom See also Examples BePerf 41 131 Gas Journal Bearing Table of Contents Gas Bearing Fixed Lobe Bearing Dimensional Analysis This option is for gas bearing application The compressible Reynolds equations are solved to obtain the equilibrium position and bearing dynamic coefficients See also Coordinate Systems Fixed Lobe Bearing Geometry Fixed Pad Gas Bearing Compressible Flow Comment Chapter Example 5 gas journal bearing Coordinates Lund Coordinates 5 ww Bearing Type Plain Cylindrical Journal and C Coordinate Angle 8 degree Units English Bearing Load 0 wl x RPM 2 x APM 2 Ee Length L 1 inch wr 129 WT 0 Ww 2 8 Diameter 1 inch Rotor Speed RPM Brg Radial Clr 0 0006 inch Start 52800 End 8 Inc 8 Ambient Pressure 147 psi Gas Dynamic Viscosity 2 e DID3 Heyn Pressurized Feed Pressure 0 Side Pressure 2 147 z L 142 Number of Pads 1 Number of amp xial Elements 4 T 360 D T 20 Save Save s Bun Cancel Gas Journal Bearing Data Sele Options Profile Chapter Example 6 g
46. 003 inch Lubricant Dynamic Viscosity 24 Mumber of Pads 3 Density 10 0301 Lbm in 3 Bearing Data for Pad 1 Leading Edge 100 Preload Trailing Edge 200 Offset Advanced Fetaures um me Open Save Save s Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber The Reynolds BC is the most realistic Advanced Features OK f Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect t Sommerfeld 2 pil used for educational purposes Oil Flooded Else English Units Angle degree Length inches Number of Axial Elements B Theta 1 Theta 2 Preload LandAre Land Radive Center Elements 100 200 60 05 0 9453 0 0077 90 0 905 220 320 60 05 0 9453 0 0077 210 0 905 340 440 60 05 0 9453 O 00 390 0 905 BePerf 84 131 Taper Land Bearing Parameters Knawn Parameters Am Length Arc Radius Arc Length s Urndercut s Undercut s Arc Radius Arc Length Arc Radius Center Offset Center Offset Center Offset LIndercut known Data Needs to know 2 data Arc Center Angle Undercuk 0 004382 Pad Leading Angle Arc Length ED D5 Pad Trailing Angle Am Radius 0 945 Bearing Radius Center Offset 0 0077 The results are present below Ell Fixed Lobe Bearing Dimensional Data Options Profile Taper Land Bearing Locomotive Turbocharger Application L 1 3 i
47. 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements E 100 200 90 0 565306 0 0025 100 0 655 220 320 90 0 565306 0 0025 220 0 658 440 90 0 565306 0 0025 240 0 655 Taper Land Bearing Parameters Knawn Parameters Arc Length Arc Radius Arc Length LIndercut LIndercut Arc Radius Arc Length Arc Radius Center Offset Center Offset Center Offset Undercut known Data Needs to know 2 data Arc Center Angle Undercuk 0 002506 Pad Leading Angle Arc Length 80 Pad Trailing Angle Are Radius 0 565306 Bearing Radius Rib Center Offset 10 0025 See also Coordinate Systems Fixed Lobe Bearing Geometry Fixed Lobe Non Dimensional Analysis Nomenclature Examples Units Lubricant Coefficients Coordinate Angle BePerf 22 131 Fixed Lobe Non Dimensional Analysis Table of Contents Fixed Lobe Bearing Non Dimensional Analysis The non dimensional bearing analysis is performed based on the given bearing eccentricity ratios e Cb The input eccentricity ratios are separated by a comma in the input string For a given eccentricity ratio an iterative procedure in determining the bearing attitude angle is repeated until the convergence criterion is satisfied The input parameters are Fixed Pad Bearing Non Dimensional Analysis Comment Fixed Lobe Non Dimensional Analysis Coordinates Standard Coordinates 4 1 Load Angle 270 degree
48. 4 mils Pmax 541 948 psi Hp 8 60247 hp Qside 0 624 gpm stiffness Lbflin 2 264E 05 0 000E 00 0 000E 00 3 008E 06 Damping Lbf slin 1 867E 03 0 000E 00 0 000E 00 6 173 03 Critical Journal Mass Lb stable The second case considered is Load Between Pivots The inputs and results are presented below BePerf 91 131 DyRoBeS C MyFolder DyRoBeS Examples Ch_6_Example_3_TPJ_LBP_coor1 TDI Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help Example from Shapiro amp Colsher 1977 and Jones amp Martin 1979 Load Between Pad L 65in D 5in Cb 0 005 in 2Cb D 0 002 Preload 0 Offset 0 5 Arc Length 60 Pivot Angle 0 Load Between Pivots Neglect Pivot Effect Bearing Data For Help press F1 Tilt Pad Bearing Dimensional Analysis Comment Example from Shapiro amp Colsher 1377 and Jones amp Martin 1373 Load Between Pad Coordinates Lund Coordinates 5 wi Analysis Constant Viscosity and C Coordinate Angle 270 degree Convert Units English Bearing Load wil 1 s RPM w2 x Lbf 2 Length L inch wl 3433 WAH 0 Wi n Diameter D 9 inch Rotor Speeds RPM Additional Speeds Brg Radial Clr 9 005 finch Stark 1000 End 25000 Inc 1000 Bearing Preload fo Number af Pads 6 Single Lubricant Dynamic viscosity 2 006 Preload P
49. 5 Damping Lbf s in T AS5E 01 1 696E401 1 696 01 2 399 02 Critical Journal Mass Lh 26 851 With the Advanced Feature OFF the laminar flow is assumed Also without Advanced Feature each finite element node has one 1 degree of freedom Le pressure is the only unknown at each finite element node With Advanced Feature ON the turbulent effect can be included or neglected Also with Advanced Feature ON each finite element node has three 3 degrees of freedom 1e pressure and pressure gradients in axial and circumferential directions are the unknowns at each finite element node With turbulent flow assumption the input parameters are shown below with Advanced Feature ON Fixed Pad Bearing Dimensional Analysis Comment High Speed Compressor Test Bearing Temperature rise Turbulent Flow Advanced Coordinates Standard Coordinates KY Bearing Type B Theelobe Analysis Option Heat Balance Convert Units Engish E Open Save Save As Bun Close Axial Length L 1 25 Joumal Dia D 1 3783 rg Radial Clr Cb 0 002 Humber of Pads 3 inich Load Angle 245 degree K and C Coordinate Angle 0 degree Bearing Load W0 w x RPM 2 s RPM 2 4E58 Ww 520 WT n We 0 Rotor Speeds RPM Additional Speeds inch Stark 48000 End 8 Inc 8 linch Bearing Data for Pad 1 Leading Edge 75 Preload 0 5454 Trailing Edge i 75 Offset 1 85
50. Bearing Type Two Axial Groove E and Coordinate Angle degree Number of Pads 2 L D 0 75 8 Bearing Data For Pad 1 Leading Edge 10 Preload 0 Trailing 170 Offset 0 Bearing Eccentricity Ratios separated by commas 0 01 0 05 0 1 0 15 0 2 0 25 0 3 0 35 0 4 0 45 0 5 0 6 0 7 0 5 0 9 Mew Open Save Saves Run Cancel Bearing Type Several bearing types are provided in the list for selection Ifthe bearing under study is not in the list select the General Fixed Profile type and input the bearing geometrical data This selection has been made for the convenience of the user since it allows the program to supply the user with typical defaults in Number of Pads Leading and Trailing Edges Preload and Offset You are free to make your changes on these default data to suit for your need Title Length Diameter Ratio L D Bearing Eccentricity Ratios e Cb String The eccentricity ratio is separated by a comma in the input string Number of Pads Npad Coordinate Systems Two coordinate systems can be used to describe the bearing geometry Pad 1 Leading Edge and Trailing Edge 9 The Leading Edge and Trailing Edge are the angles in degrees from the reference axis to the leading and trailing edges ofthe first pad For the Lund Coordinate System the reference axis is the negative Load vector W For Standard Coordinate System the reference axis 1s the positive X axis
51. Capacity is used for reference only Analysis isothermal wy Convert Units Engish psi degF Reyns Lbm in 3 gpm rpm Journal Dia D jo Axial Length L 28 memos EMT LE Brg Radial Clr Cb 802 DEJ rele ie est Mate Pad data required only when preload exists Ma of Hecesses 2 Recess Data af Pads Pad Data of Pumps Pump Data Ma of Loads E ETE Mew Open Save Save Hun Cancel Recess Pocket Data Psupply pat supply gpm Eff 0 1 o Fzupply supp Efficiency Loading Data E Load Angle degree mm Angle 12800 En 15000 ert Bn ert Fill in the data if all the recesses are identical and cyclic symmetric then all other recess data will be duplicated from the 1st recess I1 and 1 1 are the adjacent recess numbers for the ith recess indicates the slot if axial slot then i1 for the 18t recess is Position Arc bi 1 67 degree a Land Depth de do lc in Pr 10 zm Specified Specified BePerf 51 131 DyRoBeS C 31610MTybrid Rowe 5 Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubriceant Flow Hydrostatic Tools wiew Help Dae Hydrostatic Journal Test Rowe Capillary Restrictor Bearing Data L 3in Ds 3 in Ch 0 0012 in 2Ch D 0 0008 1st Recess Ang U Recess Arc 40 54 bti 1 11 45 1 11 46 2 Th
52. Center Angle Pad Leading Angle Pad Trailing 4ngle Bearing Radius Hb See also Coordinate Systems Fixed Lobe Bearing Geometry Fixed Lobe Non Dimensional Analysis Nomenclature Examples Units Lubricant Coefficients Coordinate Angle Arc Length Arc Radius Center Offset Undercut Needs ta know 2 data Undercut 0 002506 Arc Length 80 Arc Radius 0 565306 Center Offset 10 0025 BePerf 129 131 4 pads tiltng pad bearing Table of Contents Typical 4 pads tilting pad bearing See also Tilting Pad Bearing Geometry Nomenclature DyRoBeS BePerf C DyRoBeS Example Brelpj4_RigidPivot TDI Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Load Between Pivots Bearing Data L 3 25 in D 4 92 in Cb 0 00339 in 2Ch ID 0 001 34 Preload 0 06 Offset 0 5 Arc Length 80 Pivot Angle 45 Load Between Pivots Load Angle 270 Meglect Pivot Effect For Help press F1 DyRoBeS BePerf C DyRoBeS Example BreTpj4_RigidPivot 1DI Sle Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Load On Pivot Bearing Data L 3 25 D 4 92 in Cb 0 0033 in 2CbiD 0 001 34 Preload 0 06 Offset 0 5 Arc Length 80 Pivot Angle 0 Load On Pivot Load Angle 270 Pivot Effect For Help press F1 BePerf 130 131 5 pads tilting pad bearing Table of Contents Typical 5 pads t
53. Cylindrical Journal Bearing Partial Arc Bearing Two Axial Grooves Bearing Elliptical Lemon Bore Bearin Offset Halves Bearing Three Lobes Bearing Four Lobes Bearing Pressure Dam Bearing Multi Pocket Bearing Step Bearing Taper Land Bearing See also Coordinate Systems Nomenclature Fixed Lobe Dimensional Analysis Fixed Lobe Non Dimensional Analysis Examples Fixed Pad Bearing Dimensional Analysis Comment Taper Land Bearing Coordinates Standard Coordinates 5 1 Load Angle 270 degree Bearing 9 Land and Coordinate Angle 8 degree a Load W W 1 x RPM W2 x RPM 2 E55 Two Avial Groove Elliptical Lemon Bore WT 8 0 0 1 2 3 4 Offset Halves z fi B Analysis Option Units Axial Length Lie Three Lobe Four Lobe General Mult Lobes Brg Radial Cir Cb rem Pressure Dam Step Packets 9 Taper Land 10 Packet t Dynamic Viscosity 62 006 Ferns Vere 11 heneral Multi Arcs m 2 Lbm in 3 Bearing Data Far Pad 1 Leading Edge 100 Preload 8 Advanced Features Trailing Edge 200 Offset 8 Open Save Save s Burn Cancel Journal Dia BePerf 15 131 Fixed Lobe Dimensional Analysis Table of Contents Fixed Lobe Bearing Dimensional Analysis The input screen for the fixed lobe bearing dimensional analysis is shown below and the input parameter
54. Di 12 8887 13 0353 mm Do Db 20 0711 20 1854 mm Ci 0 0178 0 0571 mm Co Ci 3 211 Mr 0 0218 kg Mui 5 82554 cPoise Mua 15 2534 cPoise speed Ratio 0 240505 Load 12 18 M Rotor RPM 120000 rpm ej 0 0370 hmin 0 0176685 0 0544888 mm 154 199 81 2472 kPa Loss 1 3238 kW Kixx xy 2 N mm yy 1 10E 05 4 Mmm Cixx xy 1 01E H01 7 BB8E D1 N s mm yy 7 BB8E D1 1 41 E HI1 N s mm Koxx xy 5 85EdU2 3 48E HT3 M mm Koyx yy 4 646405 1 45E 02 Mmm Coxx xy 2 S4E 00 2 35 01 N s mm Coyx yy 2 35E D1 3 07E 00 XT Output K C For DyRoBes Rotor Test Bearing Y Z Than oe ah BePerf 39 131 Floating Ring Bearing Data Options Test Bearing Heat Balance Analysis Speed Ratio is Calculated Eccentricity Ratios Oi 4 40000 100000 120000 1400007 160000 Rotor Speed rom 0 000 Floating Ring Bearing Data KE Options Test Gearing Heat Balance Analysis Speed Ratio is Calculated Bn E NN Ring Journal Speed Ratio 40000 60000 Bn 100000 120000 140000 160000 Rotor Speed rom BePerf 40 131 Floating Ring Bearing Data E Lal Options Test Bearing Heat Balance Analysis Speed Ratio is Calculated Inne Film Power Losses Outer Film 0 00 LL 40000 600
55. DyRoBeSO BePerf Table of Contents License Agreement Introduction Getting Started How to Use Help Project Coordinate Systems Fixed Lobe Journal Bearing o Fixed Lobe Bearing Geometry o Fixed Lobe Dimensional Analysis o Fixed Lobe Non Dimensional Analysis e Tilting Pad Journal Bearing o Tilting Pad Bearing Geometry o Tilting Pad Dimensional Analysis o Tilting Pad Non Dimensional Analysis Floating Ring Bearing Gas Journal Bearing Thrust Bearing Hydrostatic Bearing Lubricant Flow Calculation PostProcessor Examples Nomenclature Non Dimensional Parameters Units References Other Topics DyRoBeS _Rotor Coefficients Coordinate Angle Plain Cylindrical Journal Bearing Partial Arc Bearing Two Axial Grooves Bearing Elliptical Lemon Bore Bearing Offset Halves Bearing Three Lobes Bearing Four Lobes Bearing Pressure Dam Bearing Multt Pocket Bearing Step Bearing Taper Land Bearing Advanced Features 4 pads tilting pad bearing 5 pads tilting pad bearing BePerf 1 131 License Agreement Table of Contents License Agreement Please review the following license agreement carefully before using the program By using this program and associated materials you indicate your acceptance of such terms and conditions In the event that you do not agree to these terms and conditions you should promptly return the package Each copy of DyRoBeSO 1s licensed to be installed and run on a single computer in a single site
56. Equilibrium Locus w r t Bearing Clearance Cb The bearing performance at 5000 rpm is shown and the results are in agreement with previous publications BePerf 70 131 VAT cm a Ell Fixed Lobe Bearing Dimensional Data Options Profile Example from Shapiro amp Colsher Sixth Turbomachinery Symp 1979 English Units L 5 in D 5 in Ch 0 0025 in 2Cb D 0 001 m 0 tilt 0 Speed 5000 rpm Load 20780 Lbf W LD 831 2 psi Vis 2E 06 Reyns Sb 0 20051 E Ch 0 5004 Att 47 2 deg hmin 1 249 mils Pmax 1964 43 psi Hp 15 753 hp 4 0 936 gpm Stiffness Lbf in 2 003 07 2 863E407 8 307 06 1 248E407 Damping Lbf s in 1 127 05 2 841E 04 2 841E 04 3 071E 04 Critical Journal Mass Lb 52875 By selecting the Standard Coordinate System an additional input for load vector 270 in this case is needed as demonstrated in File Brg 2 Axial Groove Coor2 LDI Again for comparison purposes the bearing coefficients are oriented such that the x axis is collinear with the load vector as shown in the input The results are identical with previous discussion DyRoBeS BePerf C WyFolderWMyRoBeSVExamplesWMirg 2 Axial Groove Coor Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Da Example from Shapiro amp Colsher Sixth Turbomachinery Symp 1979 English Units Y Bearing Data L 5in Ds 5 in Cb 0 0025 in
57. Groove 4 4 C uo x 1 4 4 Two coordinate systems can be used in DyRoBeS BePerf and they are described in the Coordinate Systems Section The journal static equilibrium position is defined by the journal eccentricity e and attitude angle Under dynamic conditions the journal is oscillating with small amplitudes around this equilibrium position However the bearing dynamic coefficients stiffness and damping coefficients can be calculated in any coordinate system x y z by specifying a Coefficient Coordinate Angle in the bearing input data The Coordinate Angle is measured from the X axis used to describe the bearing geometry and the load vector to x axis used to describe the bearing coefficients See Coefficients Coordinate Angle The bearing radius at minimum clearance Rb for a centered shaft can be described as the radius of the largest shaft that could be inserted into the bearing A circle drawn based on Ab ss referred to as a bearing base circle For a positive preloaded bearing pad radius is greater than bearing radius Rb and the circular pads are moved inward the bearing center Thus when the journal is centered in the bearing the pads are loaded by geometry effect The fraction of the distance between pad center of curvature and bearing center to pad radial clearance is called Preload C C when the preload is zero the pad centers of curvature coincide with the bearing cen
58. Nomenclature Ob Bearing center S O Oj X Joumalcenter 2 Pad lobe center of curvature Rb Bearing assembled radius at minimum clearance Re Pad machined radius fe Journal eccentricity distance from bearing center to journal center nm Attitude angle angle from X axis load vector to the line connecting bearing center and journal center Angle from the negative load vector negative X axis to leading edge af the first lobe Angle fram the negative load vector negative X axis to trailing edge of the first lobe Angle from the negative load vector negative axis to the line i connecting the bearing center and the pad center of curvature Bearing babhitt axial length D Bearing diameter S O Bearing minimum assembled radial clearance Cb Rh Rj Pad machined radial clearance Cp Rp Rij Preload m 1 Cb Co Y Lobe or Pad arc length y 2 amp amp Angle from leading edge to the minimum clearance point for a centered shaft for fixed lobe bearings or Angle from leading edge to pad pivot point for tilting pad bearings 7 8 P LEA Offset or Pivot Ratio amp Bit C oWO Bearing load vector Shaft rotational speed rad sec Shaft rotational speed rps Shaft rotational speed rpm Lubricant dynamic viscasity OOOO DENN The following parameters are used in the output 5 Inlet supply oil temperat
59. Pads 10 Rotor Speed rpm 3600 1 Min Film Thickness milz Bearing Load w 2000 Average Pressure 500 psi Temperature Rise 30 deg F 3 3 Cancel Tilting Pad Thrust Bearing Inlet Pressure 25 psi Tilting Pad Thrust Bearing Thrust Bearing B pads LD 7 in Pivot QD 15in Fadial Width 4 in E a Pad Length 4 75 in Pad Arc 49 48 deg BePerf 45 131 Tilting Pad Thrust Bearing Analysis Comment Tilting Pad Thrust Bearing English unita Convert Unita English Lubricant Amokon ISO VG 46 No of Fads Inlet Temperature 110 Inner Diameter 7 ir Inlet Pressure 20 psi EE in Fator Speed rpm 3600 Circ Pad Length 4 75 i Bearing Load 0000 Lbf Pad width 4 00 Arc 48 48 degree Mew Open Save Saves Bun Close Pocket Thrust Bearing Hydrodynamic Pocket Thrust Bearing Thrust Bearing 4 pockets 1 35 in 2 55in Groove 0 19 in Dam Width 0 06 in Ramp Depth 0 00225 in Pocket Depth 0 045 in Pocket Ratio 0 5 Hydrodynamic Pocket Thrust Bearing Analysis Comment DyRobeS Bepert Convert Units English Lubricant Mobil DTE Light WG 32 af Pockets 4 Inlet Temperature 125 deg F Inner Diameter ID 1 3725 iri Inlet Pressure 20 psi Outer Diameter OD 2 75 in Rotor Speed rpm 22322 Dil Groove Width D 225 in Bearing L
60. Perf 99 131 El Tilting Pad Bearing Dimensional Data Options Profile Tilting Pad Bearing with Spherical Pivot modelled as general curvatures L D 0 7622 Cb 0 0033 2Cb D 0 00134 m 0 5 Offset 0 5 Arc 72 PivAng 45 Speed 3600 rpm Load 2850 Lbf W LD 154 472 psi Vis 2 01E 06 Reyns Sb 0 43385 E Cb 0 5539 Att 0 00 deg hmin 1 635 mils Pmax 511 502 psi Hp 4 43236 hp Qside 1 293 gpm Stiffness i Lbf in 2 028 06 5 076 02 5 076 02 2 028E T06 Damping Lbf s in 4 015E 03 1 053 00 1 053 00 4 015 03 Critical Journal Mass Lb 4 8987E 10 These results are identical to case 3 For Spherical Pivot and Cylindrical Pivot the radii are always positive For General Curvatures the radi are positive if the center of curvature lies within the given body 1 the surface is convex otherwise the radii are negative Example 9 Floating Ring Bearing Floating ring bearing is commonly used in the automotive turbocharger application There are two oil films separated by a floating ring It is like two bearings in series For a conventional floating ring bearing the ring is free to rotate Then two bearings are conventional plain cylindrical journal bearings Sometimes anti rotational pin is used to prevent the ring from rotating then the outer oil film becomes a squeeze film damper The bearing type of outer film either plain journal bearing or squeeze film damper depends on the speed rati
61. T Load Angle 104 degree Analysis Option Heat Balance and C Coordinate Angle 8 degree Convert Unite English Bearing Load VD 1 x APM w2 x Length L 1 34 inch wl 560 224 WA 0 We 0 Diameter D 1 65 linch Rotor Speeds RPM Additional Speeds Brg Radial Clr D 0025 finch Start 37235 End Inc 1000 Bearing Preload 03 Single Lubricant Mobil DTE Light v5 32 Preload Number of Pads 4 Inlet Temperature 120 002 deg F Pad Arc Length IE degree Heat carried away E amp Pad Pivot Offset 0 5 Supplied Flow 4 0 25 Load Vector Load Between Pivots Integration Factor Click here Far Pad Pivat Data Pivot Type Neglect Pad Fivot Effect Save As Aun Close Tilt Pad Bearing Dimensional Analysis Comment Tilting Pad Bearing with Spherical Pivot Coordinates Standard Coordinates Y Load Angle 270 degree Analysis Option Constant Viscosity and C Coordinate Angle 0 degree Convert Units English Bearing Load 0 1 x APM 2 x 2 Length L 3 75 linch Will 2850 Ww Wi Diameter D 4 32 inch Rotor Speeds RPM Additional Speeds Brg Radial Clr U 00 33 linch Start 3400 End 3600 Inc 100 Bearing Preload 0 5 Single Lubricant Dynamic Viscosity 2 1 Reun Preload Number of Pads Pad Arc Length 72 degree 8 5 Fad Fivot Offset Load Vector Load
62. Taper Land Bearing without side dams Bearing Data L 6in Ds 6in Cb 0 005 in 0 00167 Cp 7 0 005 in Preload 0 Offset 0 Theta1 10 Theta2 1700777 Taper Arc 125 Taper Ra 3 02 UnderCut 0 01500 Taper 6 Load Angle 270 Viscosity 2E 06 Reyns Density 0 03 Lbmin 3 For Help press F1 Fixed Pad Bearing Dimensional Analysis Comment Step Bearing modelled with Type 9 Taper Land Bearing without side dams Coordinates Standard Coordinates 4 7 Load Angle 270 degree Bearing Type K and C Coordinate Angle 0 degree Analysis Option Constant Viscosity Bearing Load W0 w1 s RPM Ww sx RPM 2 4E58 Convert Units English Wi 3000 Axial Length L inch Rotor Speeds HP M WT 8 We 0 Additional Speeds Joumal Dia D 5 linch Start 17000 End 7000 Inc 1000 Brg Radial Cir 0 005 linch Lubricant Dynamic Viscosity 22 006 Reyns Humber of Pads 2 Bearing Data for Pad 1 Leading Edge fo Trailing Edge 170 Offset Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber Reynolds BC is the most realistic Gumbel half Sommerteld Gumbel and Sommerfeld BCs are only t Sommerfeld 2 used for educational purposes 10 170 0 0 125 3 02 190 350 0 0 0 0 Again with the general inputs of pressure dam bearing and taper land bearing more other types bearing be mo
63. The first coordinate system commonly referred to be Lund s convention describes the bearing geometry and load vector orientation by aligning the X axis with the load vector It is convenient in the bearing analysis The disadvantage is that the bearing geometric data are dependent upon the loading direction For a gear driven rotor load vector can be in any direction due to the power level loading condition of the rotor Then for the same bearing analyzed with different loading direction the bearing geometric data leading and trailing edges of the lobe must be re entered For the second coordinate system the bearing geometric data are independent upon the load vector Additional parameter is required to locate the load vector The loading direction is specified by an angle However it is desirable to know the stiffness and damping coefficients in the loading BePerf 11 131 direction and it s perpendicular axis Therefore a coordinate transformation may be needed to transform the bearing coefficients to the loading direction BePerf 12 131 Fixed Lobe Journal Bearing Table of Contents Fixed Lobe Journal Bearing This module performs the fixed lobe dimensional and non dimensional analyses and displays results in text and graphic forms The bearing stiffness and damping coefficients calculated from dimensional analysis be output as a bearing file to be readily used by DyRoBeSO Rotor All the input and output data can be vi
64. Uer 1 8 W J Chen All Rights Reserved Lubricant Properties Texco Regal R amp 32 Specific Gravity 66 deg F B 8665 API Gravity 68 deg F 31 80 Coefficient of Expansion F 0 0004 Pour Point deg F 22 Flash Point deg F 392 Viscosity cSt centiStake 32 cSt 212 deg F G 4 Specific Heat Cp BTU Lbm F Coefficients 0 40657 0 680495 Calculated Properties fibsolute Kinematic Uisocity Visocity Density Reyns centiPoise centiStoke_ Grams CC BTU Lb F 2 8297 7E 85 139 957 161 81 0 9092 0 53132 1 511954E 05 97 350 112 45 0 80657 8 43627 1 81275E 65 69 826 88 98 0 89023 B 545122 465627E 66 51 474 59 93 0 8588 B 55617 5 63956E 66 38 9883 45 45 0 8555 0 55112 h 35536E 06 30 022 35 23 0 8521 8 45687 3 542863E 06 23 648 27 85 0 8487 8 461 f 4 2 ae eee Bie Lubricant Charts This function allows you to compare the lubricant properties for up to 3 different lubricants The graphic results are displayed immediately on the screen The first default graph is the dynamic viscosity vs temperature You can choose Settings under the Options menu to select the desired graph data Reyn centiPoise centiStoke Specific Gravity Weight Density and Specific Heat plot type Linear Linear Linear Log Log Log and manual scaling the axes Lubricant Properties Charts Up ta 3 lubricants can be displayed in one chart Line 1 Mobil DTE Light VG 32 Line 2 Mobil DTE Medium VG
65. a must be entered separately Pad 1 Leading Edge and Trailing Edge 9 The Leading Edge and Trailing Edge are the angles in degrees from the reference axis to the leading and trailing edges ofthe first pad For the Lund Coordinate System the reference axis is the negative Load vector W For Standard Coordinate System the reference axis is the positive X axis X Preload NERO RP E C P Typical Preload value for a fixed lobe bearing ranges from 0 4 to 0 75 Offset 9 8 2 65 8 T where 18 the angle from the reference axis to the line connecting the bearing center and the pad center of curvature At this point the bearing has minimum clearance for a centered shaft and the lobe arc intersects with bearing base circle Typical Offset value for a fixed lobe bearing ranges from 0 5 to 1 0 Offset is meaningful only when preload is not zero Load Angle The load angle is needed and shown in the input screen only when the Standard Coordinate system is selected When Lund coordinate system is selected the load vector is the same as the X axis Coefficients Coordinate Angle The coordinate system x y z used to describe the bearing dynamic coefficients stiffness and damping coefficients can be different from the X Y Z coordinate system used to define the bearing geometry The Coefficients Coordinate Angle is the angle measured from the X axis For
66. ad Arc Length degree Pad Pivot Offset 0 5 Load Vector Tcal deos Click here for Neges Pasina Pad Pivat Data Pivot Type Neglect Pad Fivot Effect New Open Save Save Run BePerf 92 131 El Tilting Pad Bearing Dimensional Data Options Profile Example from Shapiro amp Colsher 1977 and Jones amp Martin 1979 Load Between Pad LID 1 0 005 2Cb D70 002 m 0 Offset 0 5 Arc 60 PivAng 0 Speed 5000 rpm Load 3433 Lbf WILD 137 32 psi Vis 2E 06 Reyns Sb 0 30343 E Cb 0 6540 Att 0 00 deg hmin 7 2 074 mils Pmax 353 22 psi Hp 8 89708 hp Qside 0 488 gpm AN Stiffness Lbflin Ko 1 149E 06 0 000E 00 Qm 0 000E 00 2 176E 06 N Damping Lbf s in 2 765E 03 0 000E 00 0 000 00 5 237E 03 Critical Journal Mass Lb Stable Example 7 4 Pads Tilting Pad Bearing compressor application A 4 pads tilting pad bearing used in a gear driven centrifugal compressor is utilized in this example The bearing load is mainly due to the gear force which increases as the speed increases For centrifugal compressor application the gear load is a function of square of the rotor speed Also to lower the bearing maximum temperature an pivot offset of 0 6 is used The bearing is oriented such that the bearing load 1s directed between pivots Note that the load vector is between pivots not pads DyRoBeS BePerf C WyFolderWDyRoBeSM xa
67. ad inertia and pivot flexibility are neglected Number of Pads Npad Coordinate Systems Two coordinate systems can be used to describe the bearing geometry Pad Arc Length degrees 8 Typical values 57 degrees for 5 pads bearings and 72 degrees for 4 pads bearings Pad Pivot Offset Tp tQ a where is the angle from the leading edge of the pad to the pivot point in the direction of shaft rotation Typical pivot offset value ranges from 0 5 to 0 65 Length Diameter Ratio L D Bearing length diameter ratio Preload m m 9 9 EX 2 E E Typical preload value ranges from 0 15 to 0 75 for tilting pad bearings Multiple preloads are allowed with a constant Cp The different preloads are separated by a comma in the input string That 15 one can enter a preload string such as 0 5 0 5 0 3 0 3 for a 4 pads bearing and 0 4 0 5 0 4 0 25 0 25 for a 5 pads bearing If only one preload value is entered then it is a constant preload bearing For multiple preloads the various Cb for each pad are calculated based on the pad preload value and the constant Cp C mHC In the data normalization preload at the loaded pad will be used That is the Cb at the loaded pad will be used as the reference Load Vector and Pivot Angle 57 The bearing can be orientated such that the load vector is directed onto the pivot between the pivots or at any arbitrarily specified pivot angle Most tilting pad bearings a
68. adial Cir Cb 0 0015 inch ARTS Lubricant Dynamic Viscosity 1 62e 006 Reyns Number of Pads 3 Density 10 03 Lbm in 3 Bearing Data Far Pad H 1 Leading Edge 100 Preload 8 Advanced Features Trailing Edge 200 Offset 8 Save Save s Bun Cancel BePerf 123 131 Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber Gumbel half Sommerfeld C Sommerfeld 2 pi used for educational purposes Oil Flooded The Renold BC ts the mast realistic Advanced Features Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel English Units Angle degree Length inches Number of Axial Elements too 100 200 220 320 340 440 Land Arc Land Radius Centerr Theta _ArcAsL Elements 0 0 0 0 Taper Land Bearing Parameters Knawn Parameters Arc Length Li LIndercut Arc Length Center Offset Known Data Pad Leading Angle Arc Center Angle Arc Radius s Undercut Arc Radius 2 Center Offset Pad Trailing Angle 200 Bearing Radius Ab 30 15 0 565306 0 0015 100 0 658 30 15 0 565306 0 0015 220 0 658 90 15 0 565306 0 0015 340 0 658 Arc Length Cancel Arc Radius C Center Offset 2 Undercut Need ta know 2 data Undercut 0 001506 Arc Length 80 15 Arc Radius l Center Offset f Fixed Lobe Bearing Dimensional Data Optio
69. al 100 Theta 2 260 Viscosity 7E 06 For Help press F1 For comparison purposes with previous publications the X axis is aligned with the load vector Lund coordinate system and constant viscosity is used in File Brg 2 Axial Groove Coorl LDI Since two lobes are identical no discontinuity in the bearing clearance and the turbulence effect is neglected therefore Advanced Feature is turned off unchecked The bearing parameters are listed below for reference BePerf 69 131 Fixed Pad Bearing Dimensional Analysis Comment Coordinates Lund Coordinates ww Bearing Type 2 Two Axial Groove K and C Coordinate Angle 8 degree Analysis Constant Viscosity Bearing Load 0 71 x Wwe x RPM 2 1 5 Convert Unis English 20780 wh 0 wa 0 Avial Length L inch Rotor Speeds RPM Additional Speeds Joumal Dia D 9 inch Start 1008 End 10000 Inc 1000 Brg Radial Clr Cb 0 0025 linch EE m Lubricant Dynamic Viscosity 2 006 lt Number of Pads 2 Density 8 Lbm in 3 Bearing Data for Pad 1 Leading Edge 100 Preload 0 Advanced Fetaures Trailing Edge 260 Offset 8 The journal equilibrium locus is shown below Ell Fixed Lobe Bearing Dimensional Data Sele Options Example from Shapiro amp Colsher Sixth Turbomachinery Symp 1979 English Units L 5 in D 5 in Cbs 0 0025 in 2Cb D 0 001 m 0 tilt 0 0 4 Journal
70. al Stiffness Tangential Stiffness 8 Lbfin Rotational Stiffness U LbFin rad Tilting Pad Bearing Dimensional Data Options Profile Tilting Pad Bearing Neglect Flexible Pivot Effect L D2 0 7622 Cbs 0 0033 2Cb D 0 00134 m 0 5 Offset 0 5 Arcs 72 PivAng 45 Speed 3600 rpm Load 2850 Lbf W LD 154 472 psi Vis 2 01E 06 Reyns Sb 0 43385 E Cb 0 5539 Att 0 00 deg hmin 1 635 mils Pmax 511 502 psi Hp 4 43236 hp Oside 1 293 gpm Stiffness Lbf in 2 114 06 0 000 00 0 000 00 2 114 06 Damping Lbf s in 4 7 33ET03 0 000 00 0 000ET00 4 733ET03 Critical Journal Mass Lb Stable Case 2 Rigid Pivot with inertia effect Pad Pivot Data Pivot Flexibility RE LL Re Inertia 1 08877 Lbm in 2 Clase Distance from Pad Center of Curvature to Pad C G 2 685 in BePerf 97 131 El Tilting Pad Bearing Dimensional Data Options Profile Tilting Pad Bearing with Rigid Pivot but free to tilt with Inertia Effect L D 0 7622 Cb 0 0033 2Cb D 0 00134 m 0 5 Offset 0 5 Arc 72 PivAng 45 Speed 3600 rpm Load 2850 Lbf W LD 154 472 psi Vis 2 01E 06 Reyns Sb 0 43385 E Cb 0 5539 Att 0 00 deg hmin 1 635 mils Pmax 511 502 psi Hp 4 43236 hp Qside 1 293 gpm Stiffness i Lbf in 2 113 06 5 437E 02 2 2 113E 06 Damping Lbf s in 4 732 03 1 035 00 1 035E 00 4 732 03 Critical Jou
71. as journal bearing L 1 in DS 1 in Cb 0 0006 in preload offset 0 speed 54000 rpm Load 12 8 Lbf WILD 12 3 psi Vis 2 E D3 Reyns Lamda 4 2315 sb 0 12791 E Cb 0 5978 Att 24 70 deg hmin 0 2414 mils Pamb 14 7 psi Prax 22 4029 D 0212345 hp Stifness 1 1 405E 04 4 252E 04 Damping iLbf s in 2 3 0 00 8 898 01 22 01 2 126 00 Critical Journal Mass stable BePerf 42 131 Gas Journal Bearing Data Options Profile Chapter Example gas journal bearing L 1 in D 1 in Cb 0 0006 in preload offset 0 rpm 52000 E Cb 0 5976 Amb Pressure 14 7 Pressure gi 22 405 3D Pressure Profile See also Examples 43 131 BePerf Thrust Bearing Table of Contents Thrust Bearing Analysis Three most commonly used thrust bearing types are included in this program They are tapered land thrust bearing tilting pad thrust bearing and hydrodynamic pocket thrust bearing The analysis 15 based on the following references 1 Machinery s Handbook by Eric Oberg Franklin D Jones and Holbrook L Horton Industrial Press Inc New York NY 10157 2 Bearing Design and Application by Donald F Wilcock and E Richard Booser McGraw Hill Book Company New York NY 1957 3 The Hydrodynamic Pocket Thrust Bearing by Donald F Wilcock ASME Trans 1955 pp 311 319 A complete FEA thrust bea
72. ate Systems Table of Contents Coordinate Systems There are two coordinate systems are commonly used by bearing analysts and rotordynamicists Coordinates ae betel Lund Coordinates X Ww tandard Coordinates s 1 Lund Convention The first Cartesian coordinate system X Y Z used to describe the bearing orientation and geometry is shown in the following figure The coordinate system is commonly used by the bearing analysts to study the bearing performance The X axis is chosen to be collinear with the bearing load vector W Note that X axis does not have to be vertically down as shown m this sketch it can be in any direction as long as X axis being aligned with the bearing load vector W i e the load vector can be in any direction Y axis is perpendicular with the X axis in the direction of shaft rotation is the circumferential angular coordinate measured from the negative load vector negative X axis in the direction of shaft rotation A typical 3 lobe bearing using this coordinate system 1s shown 9 Lund Convention 8 measured from X 84 Leading Edge gj Win X Direction 8 Trailing Edge Oil Supply Groove 4 4 a i x 1 4 4 C The lobe leading and trailing edges for a 20 degree oil supply groove are BePerf 9 131 Lobe Number Leading Edge Trailing Edge A typical 4 pads tilting pad bearing using this coordinate system is shown
73. ation If not specified 1 zero then the side leakage will be used for the temperature rise calculation For Constant Viscosity analysis a lubricant dynamic viscosity is needed Units Two unit systems are provided English or Metric units See also Units Convert Button The covert button allows you to convert the bearing input data from English to Metric or vice versa between two unit systems Length L Bearing babbitt axial length Diameter D Journal diameter Bearing Radial Clearance Cb Bearing assembled radial clearance Cb Rb Rs Preload 5 6 B 1 6 1 Typical preload value ranges from 0 15 to 0 75 for tilting pad bearings Preload Button Multiple preloads can be specified 1 different preload for different pad Currently the pad clearance is fixed 1 the pads are identical with the same pad radius While assembling the bearing different preloads can be obtained by adjusting the pad location to form different bearing clearance This restriction will be eliminated in the next release and the user can select which clearance to be fixed BePerf 29 131 Different Preloads This option allows for different preload for each pad For multiple preloads the radii of curvature of all the pads Ap are the same The Cp is kept constant Cb and preload are varied For each pad The Cb and preload in the main page will be used as a reference For constant preload case this page
74. cosity or Heat Balance option Depending upon the analysis type the input dialog box changes accordingly For Constant Viscosity analysis a non zero lubricant dynamic viscosity is required and a lubricant density is needed if turbulence effect is considered For Heat Balance option user must select a lubricant from the list input the oil inlet temperature and estimate the percentage heat carried away by oil The operating and maximum film temperatures will be calculated based on heat balance method Lubricant Dynamic Viscosity 1 5 006 Analysis Option RES lay Constant Viscosity Density 0 03 Lbm in 3 Analysis Option Lubricant Amokon ISO VG 32 NM constan eene Inlet Temperature 10 degF Heatcamied away 80 xj Units Two systems of units are provided English or Metric units See also Units Convert Button The covert button allows you to convert the bearing input data from English to Metric or vice versa between two unit systems Axial Length L Bearing babbitt axial length Journal Diameter D Journal shaft diameter Bearing Radial Clearance Cb Bearing assembled radial clearance Cb Rb Rs Number of Pads Npad Number of lobes pads separated by oil supply grooves Ifall the pads lobes are identical only the first pad data are required If there are not identical or BePerf 17 131 the Advanced Features are checked then each pad lobe dat
75. d fromthe positive X axis for Standard Coordinate System to the first pad pivot point measured in the direction of shaft rotation This angle determines the orientation of the bearing assembly When you select Specified Pivot Angle in the Load Vector selection then you need to input the Pivot Angle Load Vector Pivot Angle M5 degree Coefficients Coordinate Angle The coordinate system x y z used to describe the bearing dynamic coefficients stiffness and damping coefficients can be different from the X Y Z coordinate system used to define the bearing geometry The Coefficients Coordinate Angle is the angle measured from the X axis to the x axis Two most commonly used values for Lund Coordinate Systems are 0 1 x axis is in the loading direction and 90 degrees 1 negative y axis is in the loading direction Bearing Load W The bearing load is expressed as a second order polynomial function of rotor speed rpm This provides an opportunity to approximate the variation in load with speed BePerf 30 131 W x rpm rpm Rotor Speed rpm Start End and Increment specify a list of speeds at which calculations are to be performed Additional Speeds Ifthe Additional Speeds is checked additional speeds can be entered in additional to the speeds given by the Start End and Increment Speeds Additional 5peeds in the Analysis E Lubricant This input is for Heat Balance analysi
76. default settings by ETI will be applied You can also restore the ETI defaults by clicking the Reset button Draw Preload based on Cb is fixed otherwise Cp is fixed Draw vertical down for Std Coor System No of speed labeled in Equilibrium Locus 3 Speed labels can be overwitten by Options Sethings met lI lI lI st let lest ll tC You do not have to enter the file extension anywhere The program takes care of this extension You can open all the different bearing files for different analyses at the same time The filename for the most recent one will be displayed in the frame title If no file is open then Untitled 15 displayed the frame title BePerf 7 131 as shown below B DyRoBeS_BePerf Untitled mA Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Open Fixed Labe Dimensional File Fixed Lobe Non Dimensional File Print Tilting Flexural Pad Dimensional File Print Preview Tilting Flexural Pad Non Dimensional File Prink Setup Print to File Floating Ring Bearing Gas Journal Bearin Graphic Preferences Settings T d Land Thrust Bearing Fil 1 CMvFalderi ABrg3Lobeza ide UTE a Tilting Pad Thrust Bearing File 2 C MyFalder Brgslobe Thrust Bearing 4 C000 Test Exit Open a fixed profile bearing dimensional data File BePerf 8 131 Coordin
77. degree Journal Dia D 3 Circumferential land b 11 43 degree Axial Length L 3 Axial side land width a 0 2 0 06 48 51 deg Theta 60 00 deg b 0 30 in Brg Radial Clr Cb 10 001 2 g g Supply Pressure Pa 150 Restictor Capillary Tube Required for Flow and Power Loss Analyses Results Viscosity 5e 006 Reyne Stiffness 7075E 05 Lbf in Recess Pressure 79 Pr Ps 0 5000 de 4 Le 8 215E D8 Min de 0 0123 in Total Flow Fate 0 052877 GPM Le i 28282 de 10 035 Levde 465 22 Pumping Lass Friction Loss 0 00463 hp 0 161 hp Speed rpm 1000 Used in Friction Loss Recess Depth 10 05 Hydrostatic Journal Bearing Design Tool Convert Unita Metric mm deg MPa gram CE of Recesses E Axial Slat 0 degree Journal D 76 2 Circumferential land b 11 43 degree Axial Length L 76 2 Axial side land width a 5 09 a L 0 067 49 51 deg 2 60 00 deg b 27 54 mm Brg Radial Clr Cb 0 03048 g g Supply Pressure Pa 1 03421355 Hestrichar Capillary Tube Recess Pressure Pr 0 517106775 Pr Ps 0 5000 Required for Flow and Power Loss Analyses Results Viscosity 34 473785 cFoize Stiffness 1 5249 05 Mmm dc 4 Lc 000015102 Min de 0 3114 Total Flow Fate 0 20016 Liter Min Le 3 58371 dc 0 883 Le de 465 22 Pumping Lass Friction Loss 0 00345 kw D 12 kw Speed rpm 1000 Used in F
78. deled using these two types bearings Density 0 03 Lbm in 3 Freload 0 Advanced Fetaures Turbulence Effect L Oil Flooded idit English Units Angle degree Length inches Number of Axial Elements 8 Tools Land Radius 0 0 b 0 BePerf 89 131 Example 6 5 Pads Tilting Pad Bearing A 5 pads tilting pad bearing taken from Jones amp Martin ASLE Trans 1979 is used in this example as shown below For comparison purposes Lund s coordinate system is used that is the load vector is aligned with the X axis Lubricant viscosity is assumed to be constant and pivot pad flexibility is ignored The input parameters are shown for reference The first case considered 1s Load On Pivot DyRoBeS BePerf C WyFolderWMyRoBeSVExamplesVh 6 Example 3 TPJ LOP coor1 TDI Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help N2 Example from Shapiro amp Colsher 1977 and Jones amp Martin 1979 Load on Pad Bearing Data L 65in D25in Cb 0 005 in 2CbiD 0 002 Preload 0 Offset 0 5 Arc Length 60 Pivot Angle 36 Load On Pivot Neglect Pivot Effect For Help press F1 Tilt Pad Bearing Dimensional Analysis Comment Example from Shapiro amp Colsher 1377 and Jones amp Martin 1373 Load on Pad Coordinates Lund Coordinates 5 ww Analysis Option Constant Viscosily Convert Units English Length L 5 finch Diameter D 5 f
79. ds are identical and no discontinuity in the bearing clearance for each pad Therefore only one 1 degree of freedom at each finite element node that is pressure is unknown at each finite element node without the Advanced Feature However with Advanced Features the clearance can have sudden changes such as pressure dam bearings and taper land bearings therefore three 3 degrees of freedom at each finite element node are assumed that is pressure and pressure gradients in both axial and circumferential directions at each finite element node are unknown and are to be solved to accommodate the sudden changes in bearing clearance With Advanced Features ON the computational time will be greatly increased due to the increase of the degrees of freedom Although 3 types boundary conditions are provided one should always use Reynolds boundary condition for design and practical purposes Sommerfeld and half Sommerfeld Gumbel boundary conditions are only provided for educational and research purposes Pressure Dam Bearing Advanced Settings Circumferential Boundary Conditions Repnolds Swift Stieber The Reynolds 1 the most realistic t Bumbel half Sommerfeld Gumbel and Sommerfeld BCs are only W Turbulence Effect Ld Cancel t Sommerfeld 2 pil used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements E Pocket rc PacketDepth Pocket amp sL
80. ePerf 112 131 Two Axial Grooves Bearing Table of Contents Two Axial Grooves Journal Bearing Typical data for Lund Coordinate System e 1 100 d 260 m 0 6 0 See also Coordinate Systems Fixed Lobe Bearing Geometry BePerf 113 131 Elliptical Lemon Bore Bearing Table of Contents Elliptical Lemon Bore Journal Bearing Typical data for Lund Coordinate System e 1 100 d 7 260 m 0 5 0 5 See also Coordinate Systems Fixed Lobe Bearing Geometry BePerf 114 131 Offset Halves Bearing Table of Contents Offset Halves Journal Bearing Typical data for Lund Coordinate System 105 G 7255 m 0 5 1 1 See also Coordinate Systems Fixed Lobe Bearing Geometry BePerf 115 131 Three Lobes Bearing Table of Contents Three Lobes Journal Bearing Typical data for Lund Coordinate System e 10 E 110 m 0 5 0 5 or 1 0 See also Coordinate Systems Fixed Lobe Bearing Geometry OF BePerf 116 131 Four Lobes Bearing Table of Contents Four Lobes Journal Bearing Typical data for Lund Coordinate System e i 02 0 d 127 5 0 5 amp 0 5 or 1 0 See also Coordinate Systems Fixed Lobe Bearing Geometry BePerf 117 131 Pressure Dam Bearing Multi Pocket Bearing Step Bearing Table of Contents Pressure Dam Bearing Multi Pocket Bearing or Step Bearings In addition to the standard lobed bearings with preload and offset pressure dam pocket
81. ePerf 75 131 Fixed Lobe Bearing Dimensional Data Options High Speed Compressor Test Bearing Temperature rise Turbulent Flow Advanced ON L 1 25 in D 1 3789 in Ch 0 002 in 2Cb D 0 0029 m 0 5454 tilt 0 85 Bearing Clearance Distribution Max 0 00419 Min C 0 00200 3D FEA Mesh Data Fixed Lobe Bearing Dimensional Data Sele Options High Speed Compressor Test Bearing Temperature rise Turbulent Flow Advanced ON L 1 25 in D 1 3789 Cb 0 002 in 2Cb D 0 0029 m 0 5454 tilt 0 85 Bearing Clearance Distribution Max 0 00419 Min C 0 00700 3D FEA Mesh Data A 3 dimensional pressure profile can also be viewed BePerf 76 131 Fixed Lobe Bearing Dimensional Data E Options Profile I High Speed Compressor Test Bearing Temperature rise Turbulent Flow Advanced ON L 1 25 in D 1 3789 Cb 0 002 in 2Cb D 0 0029 m 0 5454 tilt 0 85 rpm 48000 E Cb 0 4369 Max Pressure 1162 2 3D Pressure Profile Theta Example 3 Pressure Dam Bearings A conventional pressure dam bearing is demonstrated in this example A pressure dam pocket with a constant depth is in the top lobe and a central relief track with much larger depth is in the lower lobe where the load vector is located The bearing geometry with exaggerated clearance and bearing clearance distribution are shown below DyRoBeS BePerf C M
82. effect is included Turbulent effect is included the Advanced Feature button Advanced Features The advanced features allow you to include the turbulence effect oil flooded and types of boundary conditions in the circumferential direction It also allows for the clearance discontinuity in the individual pad The Advanced Feature must be checked ON for bearings with clearance discontinuity such as Pressure Dam Bearing Multi Pocket Bearing Step Bearing and Taper Land Bearing Also for 3D pressure file plot the Advanced Feature must be checked Without Advanced Features the pads are identical and no discontinuity in the bearing clearance for each pad Therefore only one 1 degree of freedom at each finite element node that is pressure is unknown at each finite element node without the Advanced Feature However with Advanced Features the clearance can have sudden changes such as pressure dam bearings and taper land bearings therefore three 3 degrees of freedom at each finite element node are assumed that is pressure and pressure gradients in both axial and circumferential directions at each finite element node are unknown and are to be solved to accommodate the sudden changes in bearing clearance With Advanced Features ON the computational time will be greatly increased due to the increase of the degrees of freedom Although 3 types boundary conditions are provided one should always use Reynolds boundary condition for desi
83. enter is specified by 1 Arc center offset 2 Arc center angle fram Commonly amp rc Center Angle is the same as the pad leading edge angle or is located at the mid of the oil groove BePerf 127 131 Fixed Pad Bearing Dimensional Analysis Comment T aper Land Bearing Coordinates Standard Coordinates r Load Angle 270 degree Bearing Type Taper Land Y and C Coordinate Angle 8 degree Analysis Constant Viscosity Bearing Load Wil 1 x RPM 42 x RPMH 2 ES8 Units English WO B 25 8 0 Length L 782 Journal Dia D 1 1275 Brg Radial Clr Cb 0 0015 Rotor Speed RPM Stark 175000 End 75000 Inc 1000 Lubricant Dynamic Viscosity 1 Number of Pads 3 Density 1003 Lbm in 3 Bearing Data for Pad H 1 Leading Edge 100 Preload 8 iC PITE Advanced Features Trailing Edge 200 Offset 8 Save Save s Bun Cancel Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber The Reynolds BC is the most realistic Advanced Features t Gumbel half Sommerteld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel t Sommerfeld 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of amp xial Elements E 100 200 90 15 0 565306 0 0015 100 0 658 220 320 90 15 0 565306 0 0015 220 0 658 440 0
84. eta a U 2 in Depth 0 05 in Ps 150 psi Restrictor Capillary Viscosity 5E 06 Reyns Density 0 05 Lbm in 3 For Help press F1 2 Hydrostatic Hybrid Journal Bearings Pump Data E Comment Hydrostatic Journal Test Rowe Capillary Restrictor Coordinate System Standard Coordinates r theta from pos X Analysis Isothermal Psupply psi Qsupply Eff 0 1 Convert Units English in Lbf psi degF Reyne Lbm in 3 gpm rpm Eficiency Journal Dia D 3 mu POTETE BD Mice Data Viscosity 5E 06 Density 0 03 Pamb 0 Supply Pressure is the pressure before the Hestrickor Flow Capacity i used for reference only Brg Radial Clr 0 12 Load Angle degree Note Pad data required only when preload exists Not tom Ande _ Ma of Recesses E Recess Data No of Pads 0 Pad Data 1 1000 Ma of Pumps f Pump Data No of Loads fi Save Save As sete Be j Cancel ee Recess Pocket Data E Fillin the data if all the recesses are identical and cyclic symmetric then all other recess data will be duplicated fram the 1st recess I 1 and 1 1 the adjacent recess numbers for the i th recess indicates the slot if no axial slot then i1 for the 1st recess is Position Arc 1 1 1 degree a Land Depth de do lc in
85. ewed from the Text Output option while only the key output parameters are summarized in the Tabulated List and can be displayed in graphic forms Fixed Lobe Bearing Geometry Parameters used to describe the bearing geometry are defined in this section Fixed Lobe Dimensional Analysis The dimensional analysis includes Constant Viscosity analysis and Heat Balance analysis For Constant Viscosity analysis user must input a lubricant dynamic viscosity and no temperature rise will be calculated For Heat Balance analysis user must select a lubricant type and input the lubricant inlet temperature The operating and maximum film temperatures will be calculated based on the heat balance method Fixed Lobe Non Dimensional Analysis The non dimensional analysis is performed based on the given bearing eccentricity ratios See also Coordinate Systems Tilting Pad Journal Bearing Examples and Nomenclature BePerf 13 131 Fixed Lobe Bearing Geometry Table of Contents Fixed Lobe Bearing Geometry The fixed lobe bearing is made up of a number of fixed circular arc segments called lobes or pads The lobes are separated by axial lubricant supply grooves A three lobe bearing is sketched to illustrate the parameters used to describe the bearing geometry Clearances are exaggerated in the figure for illustrative purposes B lt Lund Convention measured from X 84 Leading Edge 01 W in X Direction Trailing Edge Oil Supply
86. fficients Coordinate Angle Tilting Pad Bearing Mon Dimensional Analysis Comment Tilting Pad Bearing Load Between Pivots Coordinates Standard Coordinates ev Load Angle Number of Pads 5 K and C Coordinate Angle Pad Arc Length 60 degree Length Diameter Pad Pivot Offset 05 Bearing Preload Load Vector Load Between Save Save as Bun Cancel BePerf 35 131 Floating Ring Bearing Table of Contents Hoating Ring Bearing The floating ring bearing be treated as two fluid film bearings in series The inner film bearing has two rotating surfaces journal and ring and the outer film bearing has one rotating surface ring The ring speed is calculated based on the torque balance of the ring due to inner film and outer film However the user can also specify the speed ratio in the input There are 3 options for the analysis 1 Constant viscosity user specify the inner and outer film viscosities 2 Heat Balance user specify the lubricant type and inlet temperature The program will calculate the effective viscosity based on the heat balance in the lubricant 3 Speed Dependent Variables User can specify the variables such as viscosities clearances and speed ratios as a function of speed This option 15 mainly used for the rotor time transient analysis without tedious bearing calcuation Compressoe End Bearing Y Bearing Data 11 26 mm Lo
87. figurations are studied DyRoBeS BePerf C MyFolder WyRoBeS Examples Brg_1PJ42_SphericalPivot TDI Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help Tilting Pad Bearing with Spherical Pivot Y Bearing Data L 3 75 in D 4 92 in Cb 0 0033 in 2Cb D 0 001 Preload 0 5 Offset 0 5 Arc Length 72 Pivot Angle 45 Load Between Pivots Load Angle 270 Spherical Pivot For Help press F1 BePerf 95 131 Tilt Pad Bearing Dimensional Analysis Comment Tiling Pad Bearing with Spherical Pivot 000000000 Coordinates Standard Coordinates X Y 7 Load Angle ERN degree Analysis Option Constant Viscosity and C Coordinate Angle 22 degree Convert Units Engish Bearing Load 9 0 W x RPM Ww x Lbf 2 Length L 13 75 inch Wil 2850 Ww 0 We Diameter D 4 32 linch Rotor Speeds RPM Additional Speeds Brg Radial Clr 0 0033 finch Start 3600 2600 100 Bearing Freload 5 2 Single Lubricant Dynamic Viscosity 2 16 006 Feyn Number of Pads Pad Arc Length rmm degree Pad Pivot Offset 0 5 Load Vector Load Between Pivots Click here Far Spherical Pivot Point Contact Pad Pivot Data Pivot Type Spherical Pivot Point Contact Mew Open Save Save As Aun Close Pad Pivot Data Pivot Flexibility Spherical Pivot Point Contact Pad
88. gn and practical purposes Sommerfeld and half Sommerfeld Gumbel boundary conditions are only provided for educational and research purposes Pressure Dam Bearing BePerf 19 131 Advanced Settings Circumferential Boundary Conditions Reynolds Swift Stieber The Reynolds BC i the most realistic C Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel Sommerfeld 2 pi used for educational purposes Dil Flooded English Units Angle degree Length inches Number of Axial Elements Tee tee cere 170 0 0 125 0 015 45 D 25 EE 15 350 0 0 0 0 0 1 25 Far pressure dam bearing with dam in the top pad and central relief track in the lower pad pocket arc packet arc Relief Track relief track 7 Advanced Settings Circumferential Boundary Conditions f Reynolds Swift Stieber Reynolds BC is the most realistic Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel C Sommerfeld 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements e e Thetai Theta 2 Preload Offset Packet rc PocketDepth Pocket amp sL ReliethsL Elements 10 0 0 DELE D 25 E 170 125 0 01 190 350 0 0 0 0 25 Taper Land Journal Bearing click here for more descriptions on taper land bearings
89. here dams at both sides of the taper There are some redundant inputs in the data sheet however these are entered as reference For undercut arc length arc radius and arc center offset there are only two variables are needed Click TOOLS to get other variables when only two variables are known DyRoBeS_BePerf C 222 000 LDI Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Taper Land Bearing arc center iz specified b Bearing Data Y 1 Arc center offset L 0 782 in 2 Arc center angle fram Ds 1 1276 Commonly amp rc Center Angle is Cb 0 0015 in the same as the pad leading 2Ch ID 0 00266 Ax edge angle or is located at the Cp 0 0015 in mid af the oil groove Preload 0 Offset 0 Thetal 100 Theta2 200 Taper Are 30 15 Taper Ra 0 565306 Undercut 0 00151 Taper amp xL 0 658 Load Angle 270 viscosity 1 62E 06 Density 0 03 For Help press F1 Fixed Pad Bearing Dimensional Analysis Comment T aper Land Bearing Coordinates Standard Coordinates 5 1 Load Angle 270 degree Bearing Type 8 Taper Land and C Coordinate Angle 8 degree Analysis Constant Viscosity Bearing Load V w1 s APM was RPM 2 Units English WO 2 Ww 0 Wie 0 Axial Length L 0 782 inch Boei epe BPN Joumal Dia D 1 1276 inch Start 75000 End 75000 Inc 1000 Erg R
90. ilting pad bearing See also Tilting Pad Bearing Geometry Nomenclature DyRoBeS BePerf C DyRoBeS Example Ch_6_Example_3_1PJ_LBP 1DI Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Example from Shapira amp Colsher 1977 and Jones amp Martin 1979 Load Between Pad Bearing Data L 5in Dz5in Cb 0 005 in 0 002 Preload 0 5 Offset 0 5 Arc Length 60 Pivot Angle 0 Load Between Pivots Pivot Effect For Help press F1 Bearing Data 5 5 0 005 in zu bip 0 002 Preload 0 Offset 0 5 Arc Length 60 Pivot Angle 36 Load On Pivot Neglect Pivot Effect For Help press F1 BePerf 131 131
91. inch Brg Radial Clr 0 005 linch Bearing Preload 8 Single Preload Number of Pads E 2 Pad Arc Length degree Pad Pivot Offset 05 Load Vector Load On Pivot K and C Coordinate Angle 270 degree Bearing Load 0 w APM wZ x Lb 2 WO 3433 8 Wi Rotor Speeds Additional Speeds Start 1000 End 25000 Inc 1008 Lubricant Dynamic Viscosity 2 006 Reun Click here for Pad Pivot Effect Pad Pivat Data Pivot Type Neglect Pad Fivat Effect The results are presented below Note that the bearing attitude angles are zero for the tilting pad bearings and the bearing cross coupled stiffness coefficients are also zero It indicates the inherently stable characteristics for the tilting pad bearings BePerf 90 131 El Tilting Pad Bearing Dimensional Data Options Example from Shapiro amp Colsher 1977 and Jones amp Martin 1979 Load on Pad LID 1 Cb 0 005 2Cb D70 002 m 0 Offset 0 5 Arc 60 PivAng 36 0 4 Journal Equilibrium Locus w r t Bearing Clearance Cb 0 2 0 0 4 2 0 4 0 6 El Tilting Pad Bearing Dimensional Data Options Profile Example from Shapiro amp Colsher 1977 and Jones amp Martin 1979 Load on Pad LID 1 Cb 0 005 2Cb D70 002 m 0 Offset 0 5 Arc 60 PivAng 36 Speed 5000 rpm Load 3433 Lbf WILD 137 32 psi Vis 2E 06 Reyns Sb 0 30343 E Cb 0 6000 Att 0 00 deg hmin 1 74
92. ion Lubricant Mobil DTE Light 5 32 Temperature deg 1 Diff Pressure 25 Number of Orifice Diameter in 0 11 Calculated Flow Discharge Coefficient 25272 Chamfer Flow This dialog box calculates the oil flow through chamfers BePerf 64 131 Chamfer Flow Tesco Regal 32 28 5 EMI BePerf 65 131 PostProcessor Table of Contents PostProcessor The assessment ofthe analysis results constitutes an important aspect of the entire simulation process The PostProcessor allows you to view the results in the ASCII text format and or the graphics format All the input and output data can be viewed by selecting the Text Output option The results can also be tabulated in a compact format by selecting the Tabulated List option If you decide to print the results from the Notepad go to Page Setup under File menu and adjust minimize the page margins so that the results will fit into pages In order to tabulate the results abbreviations are used See Nomenclature for their definitions In the non dimensional analysis the results are normalized in two ways The results normalized with respect to the pad radial clearance Cp are widely used in academy however the bearing radial clearance Cb is commonly used m industry for the data normalization See Non Dimensional Parameters for their definitions The non dimensional results are displa
93. lated based on the heat balance method For heat balance calculation the heat generated in the bearing is removed by the effective oil flow The effective oil flow rate depends on many factors such as the bearing construction the specified oil flow rate side leakage total circumferential inlet flow ways to supply the oil and ways to drain the oil flow etc Several cases are considered I When the supplied oil flow rate is NOT specified 1 Qsupplied 0 the side leakage will be used as the effective oil flow This is the default option and is commonly required in the bearing design process to determine the minimum required flow rate Osupplied 0 gt Qeffective Qside 2 When the specified oil flow rate is less than and equal to the side leakage 1 e Qsupplied lt Qside the specified flow rate will be used as the effective flow rate Note this starvation will result in overheated bearing and is not desirable Qsupplied lt Qside gt Qeffective Qsupplied 1 When the specified oil flow rate is greater than the side leakage 1 Qsupplied gt Qside the effective flow rate is estimated using the empirical expression Integration factor is a parameter used in the flow integration Typical value for this Q integration factor from many test data shows that the value is between 0 2 and 0 4 with an average of 0 25 to 0 3 This parameter heavily depends on the bearing construction pad shape and de
94. lecting Edit Lubricant Library The Lubricant Properties option tabulates the lubricant properties viscosity density specific heat for a range of temperatures specified in the dialog box The Lubricant Chart option displays the lubricant properties for up to 3 different lubricants in a chart for comparison proposes DyRoBe5 BePerf Untitled Project Fixed Lobe Tilting Pad Flaating Ring Sas Erg Thrust Tools view Help 3 a b Edit Lubricant Library Lubricant Properties Lubricant Charts Orifice Flow Chamfer Flow Calculate lubricant properties Edit Lubricant Library This function allows you to edit your own lubricants from the library and also to review the existing lubricants data in the library Input parameters are Lubricant Select the lubricant that you like to edit Title This title will become the lubricant identification after the data is saved Specific gravity 60 F 15 6 C Very often API is used to describe the specific gravity The API gravity and the specific gravity at 60 F are related by the following equation 141 5 Pra 1131 54 APT Viscosity centiStoke at two temperature points The viscosities cSt at 100 F and 210 F or at 40 C and 100 C are commonly published by the lubricant suppliers ASTM viscosity temperature relationship is used to calculate the viscosity at any given temperature Pour and flash points These data are entered for reference only Coefficient
95. m DyRoBesS Rotor Copyright 1991 1997 wer 1 1 Eigen Technologies Inc Wen Jeng Chen Ph D P E eC Se Ps BePerf 109 131 Coefficients Coordinate Angle Table of Contents Coefficients Coordinate Angle A Cartesian coordinate system X Y Z is used to describe the bearing geometry and load vector However the bearing dynamic coefficients stiffness and damping coefficients can be calculated in any coordinate system x y z by specifying a Coefficient Coordinate Angle in the bearing input data The Coordinate Angle is measured from the X axis used to describe the bearing geometry to x axis used to describe the bearing coefficients Ifthe Lund s convention is used to be the coordinate system two most commonly used Coefficient Coordinate Angle are 1 0 ie x axis is the loading direction 2 9 90 Le negative axis is the loading direction BePerf 110 131 Cylindrical Journal Bearing Table of Contents Plain Cylindrical Journal Bearing Typical data for Lund Coordinate System e 1 0 7 360 0 amp 0 See also Coordinate Systems Fixed Lobe Bearing Geometry BePerf 111 131 Partial Arc Bearing Table of Contents Partial Arc Journal Bearing Typical data for Lund Coordinate System e 1 120 d 9 240 for 120 degree arc and e 105 e 7 255 for 150 degree arc m 0 amp 0 See also Coordinate Systems Fixed Lobe Bearing Geometry B
96. mization Nicholas J C Gunter E J and Allaire P E 1979 Stiffness and Damping Coefficients for the Five Pad Tilting Pad Bearing ASLE Trans Vol 22 No 2 Orcutt F K 1967 The Steady State and Dynamic Characteristics of Tilting Pad Journal Bearing in Laminar and Turbulent Flow Regimes Journal of Lubrication Technology Shapiro W and Colsher R 1979 Dynamic Characteristics of Fluid Film Bearings Proc Sixth Turbomachinery Symp Shang L and Dien I K 1989 Matrix Method for Computing the Stiffness and damping Coefficients of Multi Arc Journal bearings STLE Tribology Transactions Wilcock D F and Booser E R 1957 Bearing Design and Application McGraw Hill New York Young W C 1989 Roark s Formulas for Stress amp Strain Sixth Edition McGraw Hill Book Company pp 650 652 BePerf 108 131 DyRoBeSO Rotor Table of Contents DyRoBeSO Rotor DyRoBeSO Rotor is a powerful rotor dynamics program based on Finite Element Analysis FEA This program has been developed for the analysis of free and forced vibrations Lateral Torsional and Axial of mult shaft and multi branch flexible rotor bearing support systems The lateral vibration of the discretized rotor system is described by two translational x y and two rotational 6 coordinates at each finite element station Le 4 degrees of freedom at each shaft station The motion of a flexible support is described by two additional tran
97. mplesWirg TP J Heat Balance 5 TDI Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help 4 Pads TPJ Compressor Applicatin Bearing Data L 1 9685 in D 2 1654 in Cb 0 0029 in 2Cb D 0 003 Preload 0 3 Offset 0 6 Arc Length 72 Pivot Angle 27 Load Between Pivots Load Angle 252 Qsup 5 gpm Q factor 0 25 Neglect Pivot Effect For Help press F1 BePerf 93 131 Tilt Pad Bearing Dimensional Analysis Comment 4 Pads TPJ Compressor amp pplicatin Coordinates Standard Coordinates T Analysis Heat Balance Convert Units English Length L 1 B85 inch Diameter D 2 1554 finch Brg Radial Clr Cb 10 0029 finch Bearing Preload 03 Single Preload Number of Pads 422 Arc Length EIN degree Pad Pivot Offset 0 6 Load Vector Load Between Pivots Load Angle 252 degree K and Coordinate Angle 8 degree Bearing Load VD 1 x RPM 2 x LBA z wt 0 wh Wi 1 2e 006 Rotor Speeds APM Additional Speeds Start 10000 End 40000 ine 1000 Lubricant Mobil DTE Light 32 Inlet Temperature 110 dea F Heat carried away E amp Supplied Flow 5 BP 0 25 Integration Factor Click here for Pad Pivat Data Pivot Type Neglect Pad Fivot Effect Some results are shown below L Tilting Pad Bearing Dimensional Data Options 4 Pads TPJ Compressor Applicatin L D 0
98. n D 1 8898 in Cb 0 003 in 2Cb D 0 00317 m 0 tilt 0 Speed 25000 rpm Load 20 Lbt W LD 8 14087 psi Vis 2 16E 06 Reyns Sb 10 967 E Ch 0 0281 Att 33 84 deg hmin 2 916 mils Pmax 320 705 psi Hp 4 96052 hp Qside 1 173 gpm Stiffness Lbf in 2 022 05 1 261E 05 1 311 05 2 072 05 Damping Lbf s in 1 118 02 6 160E 01 5 063 01 1 162E 02 Critical Journal Mass Lh 62 088 BePerf 85 131 Fixed Lobe Bearing Dimensional Data Options Profile Taper Land Bearing Locomotive Turbocharger Application L 1 3 in D 1 8898 in 0 003 in 2Cb D 0 00317 m 0 tilt 0 rpm 25000 0 0281 Max Pressure 320 71 3D Pressure Profile Fixed Lobe Bearing Dimensional Data PRSE Options Profile Taper Land Bearing Locomotive Turbocharger Application L 1 3 in D 1 8898 in 0 003 in 2Cb D 70 003 17 m 0 tilt 0 rpm 25000 0 0281 Max Pressure 320 71 3D Pressure Profile With this more general inputs a pressure dam bearing without relief track can also be modeled with this bearing type Example 5 Step Bearing When the axial length of a pocket equals to the bearing axial length it forms a step A step bearing can be modeled using Type 8 Pressure Dam Bearing with PocketAxL equals to the bearing axial length as demonstrated below BePerf 86 131 DyRoBeS BePerf C MyFolder DyRoBeS Examples Bre_ Step Brg
99. n Redraw ple Titing Pad Bearing File C BecoenBePerf s PDFilev amp 0L DOSOD S0 TSG e E OL m Ca um Im uw mqi nw uw mqi um ca mi mqi Ca Sommerfeld Number BePerf 66 131 Es Fixed Lobe Bearing Dimensional Data Ioj x Options Two Axial Groove Bearing Example from Shapiro amp Co L 5 D 5 Ch 0 0025 preload 0 offset 0 Journal Equilibrium Locus 4 w rt Bearing Clearance 1 1 1 Es Fixed Lobe Bearing Dimensional D ata Oy x Options Profile Two Axial Groove Bearing Example from Shapiro amp Colsher L 5 D 5 0 0025 prelaad 0 affset 0 Rotor Speed 5000 rpm Eh 0 5004 Attitude Angle jT 22 Hmin Cb 0 4996 Maximum Film Pressure 1854 11 deg Frictional Power Lass 15 75 Stifness 2 003E 07 2 80863E 07 5 307E 06 1 24868E 07 Damping 1 127E 05 2 941 04 2 B841E 04 3 071 04 Critical Journal Mass 137 Es Fixed Lobe Bearing Dimensional D ata DE XLI Options Two Axial Groove Bearing Example from Shapiro amp Colsher L 5 D 5 Ch 0 0025 preload 0 offset 0 Minimum Film Thickness Hrnin C b 1500 3000 4500 7500 9000 10500 1200015500 15000 Rotor Speed BePerf 67 131 E Tilting Pad Bearing Non Dimensional Data Options Normalization Example Tilting Pad Bearing 5 Pads UD 0 5 Offset 0 5 Preload 0 Pivot Angle 25 ap om po
100. nate System Standard Coordinates psr theta from pos X Analysis Heat Balance Convert Unita Metric mm Newton MPa degC cPoise gram CE rpm Flow Capacity i used for reference only Psupply MPa Qsupply lpm Eff 0 1 Efficiency 12 5 100 0 75 Joumal Dia D 79 984 Lubricant Mobil DTE Light MG 32 45 e Loading Data X 36 c Axial Length L Pamb Brg Radial Chr Cb 0 066 Note Pad data required only when preload exists mm Load Ande No of Recesses 4 Recess Data Ma of Pads 0 Pad Data 10000 490 2 15000 490 af Pumps Pump Data Ma of Loads 3 Load Data 20000 490 Load Newton Angle degree Recess Pocket Data Fillin the data if all the recesses are identical and cyclic symmetric then all other recess data will be duplicated from the 1st recess 1 and 1 1 are the adjacent recess numbers far the ih recess o indicates the slot IF no axial slot then i1 for the 1st recess is NA Position Arc bi 1 bre degree a Land Depth dc do le mm Pr MPa lpm 1 Orifice 15 Orifice 15 Orifice 15 Hydrostatic Journal Analysis Design Tool This tool is provided for the restrictor design BePerf 55 131 Hydrostatic Journal Bearing Design Tool Convert Units English psi Lbm in 3 of Recesses Axial Slot 0
101. nced Settings Circumferential Boundary Conditions f Reynolds Swift Stieber The Reynolds BC is the most realistic Advanced Features ok t Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect Cancel t Sommerfeld 2 pi used for educational purposes Oil Flooded English Units Angle degree Length inches Number of Axial Elements E Lobe Land Radius am 100 200 3015 0 565306 0 0015 EN 220 320 3015 0 565306 0 0015 340 440 90 15 0 565306 0 0015 100 0 655 220 0 655 340 0 655 BePerf 21 131 Taper Land Bearing Parameters Knawn Parameters Arc Length Arc Radius Arc Length Undercut Undercut Arc Radius Am Length gt Arc Radius y Center Offset Center Offset Center Offset LIndercut Known Data Needs to know 2 data Arc Center Angle LI ndercut 0 001506 Pad Leading Angle Arc Length poi Pad Trailing Angle Arc Radius 0 565306 Bearing Radius Ab Center Offset ooms For Taper Land Bearing the undercut and taper length are normally specified in the design process however the arc center and arc radius are typically specified in the manufacturing drawings A Tools button is provided for this conversion Advanced Settings Circumferential Boundary Conditions f Reynolds Swift Stieber The Reynolds BC is the most realistic i Advanced Features Gumbel half Sommerfeld Gumbel and Sommerfeld BCs are only Turbulence Effect t Sommerfeld
102. ng the bearing stiffness is mainly influenced by the Pr Ps however the recess pressure is controlled by the flow through the land and the restrictor capillary orifice etc For more information on the hydrostatic bearmng design H C Rippel Design of Hydrostatic Bearings Machine Design Part 1 10 Aug 1 to Dec 5 1963 J P O Donoghue and W B Rowe Hydrostatic Bearing Design Tribology Vol 2 Feb 1969 A Cameron Basic Lubrication Theory 1981 J Frene etc Hydrodynamic Lubrication Bearings amp Thrust Bearings Editor D Dowson Elsevier 1990 W B Rowe Hydrostatic Aerostatic and Hybrid Bearing Design Elsevier 2012 Since the design of the hydrostatic bearing is mainly in the restrictor design therefore a design tool is also provided in this program Hydrostatic Hybrid Journal Analysis All the inputs are selfexplanatory the recess data are described below Slot i Recess j recess are Theta 0 position For recess I the recess position is measured from theta 0 to the center of the recess Note that the oil supply hole may not be at the center in many situations But that does not affect the recess pressure Recess position is used to identify the recess location 1 1 is the previous recess number it can be 0 1f I is connected to the slot not another recess I 1 is the next recess number it can be 0 1f I is connected to the slot not
103. ns Taper Land Bearing L 0 762 in D 1 1275 in Cb 0 0015 in 20 bYO 0 00266 m D tilt 0 Clearance Distribution BePerf 124 131 Fixed Lobe Bearing Dimensional Data Options Profile Taper Land Bearing L 0 782 in D 1 1275 in Cb 0 0015 in 2Cb D D D O55 m 0 tit 0 Pressure Distribution Fixed Lobe Bearing Dimensional Data Options Profile L 0 782 in OF 1 1275 in Cb 0 0015 in 2Ch 0 0 00266 m 0 tit 0 speed 75000 rpm Load 6 26 Lbf VLD 7 09925 psi Vis 1 62E Ub Reyns cb 40 296 E Cb 0 0065 Att 22 11 deg hmin 1 49 mils Pmax 776 176 psi Hp 7 34765 hp stiffness S B1ISE HIS 3 238 S 405E 05 5 Damping Lbf s in O 695E H 1 1 566E 00 S29E 00 3 765641 Critical Journal Mass 0 03836 See also Coordinate Systems Fixed Lobe Bearing Geometry and Examples BePerf 125 131 Advanced Features Table of Contents Advanced Features The advanced features allow you to include the turbulence effect oil flooded and types of boundary conditions in the circumferential direction It also allows for the clearance discontinuity in the individual pad The Advanced Feature must be checked ON for bearings with clearance discontinuity such as Pressure Dam Bearing Multi Pocket Bearing Step Bearing and Taper Land Bearing Also for 3D pressure file plot the Advanced Feature must be checked Without Advanced Features the pa
104. o specified in the input In this example the ring is free to rotate DyRoBeS BePerf C MyFolder DyRoBeS Examples Bre_ Turbocharger2 FRB Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools view Help Dg M Turbocharger Floating Ring Example page 279 Y Bearing Data Li 0 4 in Lo 0 5 in Ds 0 4332 in Di 0 434 in Do 0 75 in Db 0 7525 in d Mr 0 037 Lbm Mui 1E 06 Reyns Muo 2bE 06 Reyns Speed Ratio 0 2 Ci 0 0004 in Co 0 00125 in Co Ci 3 125 Load Angle 270 For Help press F1 BePerf 100 131 Floating Ring Bearing Comment Turbocharger Floating Ring Example page 273 Coordinates Standard Coordinates 7 Load Angle 270 degree Convert Unis English Shaft Diameter Dis 10 4332 inch Bearing Diameter Db 0 7525 inch Floating Ring Data Mass mr 10 037 Lbm Inner Length Li linch 0 4 Outer Length Lo 0 5 finch Inner Diameter Di 10 434 inch Outer Diameter Do 8 inch K and Coordinate Angle 0 degree Bearing Load ww 41 x RPM 42 x RPM 2 Lbf Ww 05 Ww 0 Wee Rotor Speeds RPM Additional Speeds Start 100000 End 150000 Inc 10000 Inner Film Viscosity 1 Outer Film Viscosity 2 006 Ring Shaft Speed 02 Ci 0 0004 Co 0 00125 Co Ci 3 125 Estimated Speed Ratio 0 194117 Mew Open Save Save Buri
105. oad Ww 73 Dam Width 0 065 iri Ramp Depth 0 0032 iri Pocket Length 05 Pocket Depth D 05 ir Open Save saveds Close sample outputs from the program ThrustBrg BePerf 46 131 Graphic Output Options Display ae Tilting Pad Thrust Bearing 29 Cae Case D Pressure Distribution Prin 0 000 Pmax 1210 751 psi BePerf 47 131 Graphic Output Tilting Pad Thrust Bearing Temperature ne 2 2 Va Case 0 Film Thickness hotvot 1 85771 hmin 1 05211 hmax 3 8853 mils 1 05211 BePerf 48 131 Graphic Output PREIEJ Options BEES Pressure Tilting Pad Thrust Bearing 166 095 135 238 Case 0 Temperature Tsup 120 00 Tmin 136 24 Tmax 188 08 T 75 166 12 BePerf 49 131 Hydrostatic Bearing Table of Contents Hydrostatic Hybrid Bearing Analysis Hydrostatic journal bearing design is very different from the design of hydrodynamic bearings Many design concepts are fundamentally different such as increasing the load or bearing eccentricity will increase the bearing stiffness due to the higher hydrodynamic resistance for a hydrodynamic bearing However increasing the load or bearing eccentricity for a hydrostatic bearmg may lower the bearing stiffness due to the higher pressure ratio Pr Ps Recess pressure supply pressure For hydrostatic beari
106. ral file extensions are used for different bearing types They are LDI for Fixed Lobe Dimensional Analysis LNI for Fixed Lobe Non Dimensional Analysis TDI for Tilting Pad Dimensional Analysis TNI for Tilting Pad Non Dimensional Analysis FRB for Floating Ring Bearing GDI for Gas Journal Bearing TLT for tapered land Thrust Bearing TPT for tilting pad Thrust Bearing POC for pocket Thrust Bearing HSJ for Hydrostatic Bearing Default Settings _Colo __ Size J Header T itle Font Settings L1 5000259 SES mE 2 nra 55 128 255 amp AGE 000 000 2551 ncGBy32132152 Label Font Settings Font Arial Style Regular Arial SIZE Auto Scale Draw Bearing Geometry with exaggerated clearance 4 hRGEBm128128 128 Line Size in General 2 Open Save Heset Close Graphic Preferences Settings allows you to set your own preferences settings for many graphic features You can save these settings into a preference file such as one for screen display one for printer output To change color for a specific setting simply click the RGB color value to open the Color Dialog Box for selection as illustrated in the following figure The startup preferences file named MyPreferences bpf will be automatically opened and applied when DyRoBeS BePerf is activated This will be your own default startup file If MyPreferences bpf file does not exist the
107. rated by the lubricant shear force is carry away by the lubricant Floating Ring Bearing Comment Compressoe End Bearing Coordinates Standard Coordinates 5 1 Convert Units Shatt Diameter Ds Bearing Diameter Db Floating Ring Data Mass mr Inner Length Li Outer Length La Inner Diameter Di Outer Diameter Do Metric 12 833 1201 594 rnm mm kg mm mm mm mmn Load Angle 80 degree K and C Coordinate Angle 8 degree Bearing Load WD x RPM 2 s RPM 2 N WO WT 8 Whe 8 Rotor Speeds RPM Additional Speeds Shark 60000 End 150000 Inc 6000 Analysis Hing Speed Calculated from Torque Balance Lubricant Typical SAE 10w 40 Inlet Temperature 80 degC Supply Flow 0 Ipm Heat Carry Away 80 Ci 0 0178 0 05715 Co Ci 3 2107 Ra Riz 1 2440 Estimated Speed Aatio 0 3509 New Open Save Save Bun Close Speed Dependent Variables specify the viscosities clearances and speed ratios vs rpm if known BePerf 37 131 Floating Ring Bearing Comment Test Bearing Coordinates Standard Coordinates 5 Convert Units Shaft Diameter Ds Bearing Diameter D b Floating Data Mass mr Inner Length Li Outer Length La Inner Diameter Di Outer Diameter Do Metric 12 8337 1201 094 mm kg mm rnm mm mm
108. re designed such that the pivots are symmetrical with respect to the load vector i e the load is directed onto a pad pivot or between two pivots When you select either Load on Pivot or Load between Pivots then you do not need to input the Pivot Angle The Pivot Angle will be calculated and updated automatically for you in these two cases Pivot angle is the angle in degrees measured from the Negative Load Line for Lund s Coordinate System and measured from the positive X axis for Standard Coordinate System to the first pad pivot point measured m the direction of shaft rotation This angle determines the orientation of the bearing assembly When you select Specified Pivot Angle in the Load Vector selection then you need to input the Pivot Angle Coefficients Coordinate Angle The coordinate system x y z used to describe the bearing dynamic coefficients stiffness and damping coefficients can be different from the X Y 2 coordinate system used to define the bearing geometry The Coefficients Coordinate Angle is the angle measured from the X axis to the x axis Two most commonly used values for Lund Coordinate Systems are 0 1e x axis is in the loading direction and 90 degrees 1 negative y axis is in the loading BePerf 34 131 direction Comments See also Coordinate Systems Tilting Pad Bearing Geometry Tilting Pad Dimensional Analysis Nomenclature Examples Fixed Lobe Bearing Geometry Non Dimensional Parameters Coe
109. rg Outer Film EMyFolde DyR oaBeS5 Example E samples T urbachargerzLluter brg When outputs the bearing stiffness and damping coefficients three files will be created One is for the total impedance which synchronous excitation 1s assumed The other two are the bearing stiffness and damping coefficients for the inner and outer films It depends on how the rotor system is modeled The users can make their decision on how to use these files Example 10 A 3 Lobe Gas Bearing A 3 lobe gas bearing is used in this example The input parameters are shown below DyRoBeS BePerf C MyFolder DyRoBeS Examples Bre_ GasBearing3 GDI Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help 3 Lobe Gas Bearing Y Bearing Data L 1in Ds 1in Cb 0 0006 in 2Cb D 0 0012 9 Cp 7 0 0012 in x Preload 0 5 Offset 0 5 Thetal 90 Theta2 210 Load Angle 270 Viscosity 2 7E 09 Reyns Ambient P 14 7 psia Side P 14 7 14 7 psia For Help press F1 BePerf 102 131 Fixed Pad Gas Bearing Compressible Flow Comment A3LebeBasBeaig 000000 Coordinates Standard Coordinates CY Load Angle ERN degree Bearing Type Three Lobe E and Coordinate Angle mE degree Convert Units English Bearing Load w 1 x RPM w2 x RPM 2 Length L finch wo 129 wr wap Diameter D inch Rotor Speeds RPM Additional Speeds Brg Radial Clr
110. rical Pivot the radi are always positive For General Curvatures the radii are positive if the center of curvature lies within the given body 1 e the surface is convex otherwise the radii are negative The pivot stiffness is derived from the deflection equation references Young and Hamrock Caution must be taken when input Rotational Stifness for Flexure Pad Bearing The pad assembly method for tilting pad bearing is based on the assumption that the pads are free to tilt about the pivot points Pad Pivot Data E3 Pivot Flexibility Neglect Pad Prvot Effect es PadMasz D Rigid Pivot Free to Tilt with Inertia Effect LEm in 2 Close Spherical Pivot Point Contact Distance from Py Cylindrical Pivot Line Contact in General Curvature Constant Stiffness Poisson s Ratio 10 33 0 29 Elastic Modulus 0 000 29000000 LbfZin 2 Radius 512 5 125 Pad Pivot Data Pivot Flexibility e m c Pad Mass 10 Inertia 8 Lbm in 2 IBS Distance fram Pad Center of Curvature to Pad C G 8 iri Pad Data Housing Data Poisson s Ratio 8 n Elastic Modulus 8 n Lbf in 2 Radius 8 n in Effective Length 8 iri Axial Radius 8 in Radial Stiffness Tangential Stiffness Rotational Stiffness U Lbf in rad Pad Pivot Data Inertia Lbm in 2 Close Distance fram Pad Center of Curvature to Pad C G 8 in
111. riction Loss Recess Depth 4 BePerf 56 131 Hydrostatic Journal Bearing Design Tool Convert Units English in psi reynes Lbm in 3 of Recesses Axial Slot 0 degree Journal Dia D 3 Circumferential land b 11 43 degree Axial Length L 3 Axial side land width a 0 2 0 067 Rec 49 51 deg 2T heta 60 00 deg b 0 30 in Brg Radial Clr Cb 10 0012 9 g Supply Pressure Pa 150 Restictor Orifice Feed Recess Pressure 78 Pr Ps 0 5000 Required Far Flow and Power Loss Analyses Results Viscosity 5e 006 Reyns Elite Density 0 03 1 0788E 06 4 07E 05 2 do 0 0072 in for Cd 0 6 Total Flow Fate 0 052877 GPM Cd 05 da 00072 Pumping Lass Friction Lass Speed rpm 1000 Used in Friction Lass iab 0 00463 hp 0 161 hp Recess Depth 10 05 Hydrostatic Journal Bearing Design Tool Convert Unita Metric mm deg MPa cPeize gram CE of Recesses E Axial Slat 0 degree Journal D 76 2 Circumferential land b 11 43 degree Axial Length L 76 2 Axial side land width 5 08 a L 0 067 49 51 deg 2 60 00 deg b 27 54 mm Brg Radial Clr Cb 8 3048 g g Supply Pressure 1 03421355 Restrictor Orifice Feed Pr Psz 0 5000 Recess Pressure Pr D 517105775 Required for Flow and Power Loss Analyses Results Viscosity 34 473785 cPoize Ciffmess Density 0 830397 gram CC 1 85893E 05 Mmm
112. ring analysis is also available DyRoBeS ThrustBrg which analyzes various thrust bearings with the Reynolds equation coupled with the energy equation in unt or bidirectional rotations Both pressure and temperature distribution can be obtained in this FEA program This 1 a separate program from BePerf DyRoBeS BePerf Untitled Tilting Pad Thrust Hydrodynamic Pocket Thrust Tapered Land Thrust Bearing Analvsis Taper Land Thrust Bearing Tapered Land Thrust Bearing Thrust Bearing B pads ID 1 625 in O 0 3in Groove 0 1 in ID Taper 0 005 in OD Taper 0 003 in BePerf 44 131 Tapered Land Thrust Bearing Analysis Comment High Speed Compressor Thrust Bearing Convert Units English Lubricant Amokon ISO VG 32 Ma af Pade E Inlet Temperature 122 dea F Inner Diameter 1 B25 ir Inlet Pressure 20 pi Outer Diameter OD 3 irj Rotor Speed rpm 29000 Oil Groove Width ir Bearing Load w 1040 Tapers OID 10 0030 0 0050 finches or 0 07623 0 1270 mm Taper Value c amp OD 0 003 ir D 10 005 in Open Save Aun Close Taper Land Thrust Bearmg Design Tool Tapered Land Thrust Bearing Design Tool Comment Taper land Thrust Bearing Design Tool Convert Units English Lubricant Mobil DTE Light WG 32 Inner Diameter 5 1 in Inlet Temperature 140 deg F Design Criteria limits of
113. ring is employed m this example It is machined out of a standard 3 axial groove bearing as shown in figures below Again the clearances arc center offset and undercut are exaggerated for illustration purposes Each lobe is machined with an arc to form the tapered land The arc has a radius of Ra and the arc center is specified with a center offset ofr and an angle Theta measured from the reference axis X axis The arc center angle normally is either in the middle of the oil groove or the same as the leading edge of the lobe Typically there are side dams in the tapered land area similar to the pressure dam bearmg When taper arc axial equals to the bearing axial length no side dam exists The circumferential taper arc length is normally not specified for a tapered land bearing since it will be the end ofthe arc However this arc length can be specified to forma step in the tapered land area DyRoBeS BePerf C MyFolder DyRoBeS Example BePerfibre_ 1 Ty Sele Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow View Help Taper Land Bearing Locomotive Turbocharger Application Bearing Data L 1 3in Ds 1 8898 in taper Cb 0 003 in are Cb D 0 00317 F Cp 0 003 in 4 Preload 6 Offset 0 Thetal 100 Theta 2 204 Taper Arc 60 05 Taper Ra 0 9453 UnderCut 0 00493 Taper AxL 0 505 Load Angle 2760 Viscosity 2 16E 06 Density 0 0301 For Help
114. rnal Mass Lb 6 1811E 10 Case 3 Spherical Pivot this is the true configuration Pad Pivot Data Pivot Flexibility Spherical Pivot Point Contact Pad Mass 11 1351 Lbm Inertia 1 08877 Lbm in 2 Blocs Distance fram Pad Center of Curvature to Pad C G 2 685 in Pad Data Housing D ata Poisson s Ratio 0 22 10 29 Elastic Modulus 1 00000 129000000 LbfZin 2 Radius 5 12 5 125 BePerf 98 131 El Tilting Pad Bearing Dimensional Data Options Profile Tilting Pad Bearing with Spherical Pivot L D 0 7622 Cb 0 0033 2Cb D 0 00134 m 0 5 Offset 0 5 Ares 72 PivAng 45 Speed 3600 rpm Load 2850 Lbf W LD 154 472 psi Vis 2 01E 06 Reyns Sb 0 43385 0 5539 Att 0 00 deg hmin 1 635 mils Pmax 511 502 psi Hp 4 43236 hp Qside 1 293 gpm Stiffness Lbf in 2 028E 06 5 076 02 5 076 02 2 028 06 Damping Lbf s in 4 015E 03 1 053E 00 1 053 00 4 015E 03 Critical Journal Mass Lb 4 8987 10 Case 4 General Curvatures The spherical pivot can be modeled using this more general input Pad Pivot Data Pivot Flexibility Pad 11 1351 Lbm Inertia 1 08877 Lbm in 2 Close Distance fram Pad Center of Curvature to Pad C G 2 685 in Pad Data Housing D ata Poisson s Ratio 0 33 Elastic Modulus 18000000 29000000 Lbf in 2 Radius 5 12 5 125 in Axial A adius 5 12 2125 Be
115. s are also described below Fixed Pad Bearing Dimensional Analysis Comment High Speed Compressor Test Bearing Temperature rise Turbulence effect 0000002 Coordinates Standard Coordinates Load Angle 230 degree Bearing Type 5 TheeLobe K and Coordinate Angle jo degree Analysis Option HeatBalance Bearing Load WI w1 x RPM W2 x RPM 2 158 Convert Units Engin Wi po Ww UM we een Axial Length L 1 25 inch Rotor Speeds RPM Additional Speeds Journal Dia D 1 3 83 linch Start 8000 End 50000 Inc 1000 Brg Radial Clr 0 002 inch Lubricant Mobil DTE Light MG 32 Number of Pads 3 Inlet Temperature 120 degF Bearing Data for Pad 1 Heat carried away 80 4 Leading Edge 6 Preload 0 5454 Advanced Fetaures Trailing Edge 160 Offset 0 85 Open DyRoBeS_BePerf C BePerf_Example Brg_3 Lobe_HeatBalance1b LDI Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help High Speed Compressor Test Gearing Temperature rise Turbulence effect Y Bearing Data L 1 25 in Ds 1 3788 in Cb 0 002 in 2Cb D 0 0029 Cp 0 00439947 in Preload 0 5454 Offset 0 05 Thetal 60 Theta2 160 Load Angle 230 For Help press F1 Comment This is used to describe the bearing under study Coordinates BePerf 16 131 Two coordinate systems can be used to describe the bearing geometry
116. s option Ifthe lubricant you want is not in the list you can enter it from the Edit Lubricant Library under the Lubricant menu Inlet Temperature This input is for Heat Balance analysis option Percent Heat carried Away by Lubricant This input is for Heat Balance analysis option Typical value is between 75 90 default is 80 Lubricant Supply Flow This input is for Heat Balance analysis option If non zero value is specified the temperature rise will be calculated based on this flow rate Otherwise the side leakage will be used m the temperature rise calculation In the tilting pad bearing design end seals are commonly used to reduce the side leakage and the oil flow rate is controlled by either oil supply orifices or drain holes For heat balance calculation the heat generated in the bearing 15 removed by the effective oil flow The effective oil flow rate depends on many factors such as the bearing construction the specified oil flow rate side leakage total circumferential inlet flow ways to supply the oil and ways to drain the oil flow etc Several cases are considered I When the supplied oil flow rate is NOT specified 1 Qsupplied 0 the side leakage will be used as the effective oil flow This is the default option and is commonly required in the bearing design process to determine the minimum required flow rate Osupplied 0 gt Qeffective Qside 2 When the specified oil flow rate 15 less
117. sign the orifice configuration ways of supply oil ways of drain oil etc Tilting Pad Non Dimensional Analysis The non dimensional analysis is performed based on the given bearing eccentricity ratios See also Coordinate Systems Fixed Lobe Journal Bearing PostProcessor and Examples BePerf 25 131 Tilting Pad Bearing Geometry Table of Contents Tilting Pad Bearing Geometry A 5 pad tilting pad journal bearing 15 shown schematically in the following figure Clearances are exaggerated in the figure for illustrative purposes W Pivot Angle Lund Convention measured from ii W in X Axis W Pivot Angle Convention measured from X w measured from X Mu Y Pivot FN Me 1 x 1 8 Oj Op jw 3 Two coordinate systems can be used in DyRoBeSO and they are described in the Coordinate Systems Section The journal static equilibrium position ts defined by the journal eccentricity e and attitude angle Under dynamic conditions the journal is oscillating with small amplitudes around this equilibrium position However the bearing dynamic coefficients stiffness and damping coefficients can be calculated in any coordinate system x y z by specifying a Coefficient Coordinate Angle in the bearing input data The Coordinate Angle is measured from the X axis used to describe the bearing geometry to x axis used to describe the bearing coefficients See Coefficients Coordinate Angle
118. slational displacements x y For flexible disks two additional rotational displacements are introduced That 1s for a flexible disk a total of six 6 degrees of freedom is required to describe the motion of the disk The analyses for lateral vibration contain Static Deflection amp Bearmng Constraint Reactions Critical Speed Analysis Critical Speed Map Analysis Whirl Speed amp Stability Analysis Steady State Synchronous Response Analysis Steady State Harmonic Excitations Time Transient Analysis Steady Maneuver Load Analysis For torsional vibration the motion of each finite element station is described by a rotational displacement 6 The systems can be continuous discrete or the combination of continuous and discrete model The analyses for the torsional vibration are Undamped and Damped Natural Frequencies Calculation Steady State Forced Response Analysis Transient Startup Analysis with speed dependent excitation Transient Analysis with time dependent excitation For axial vibration the motion of each finite element station is described by a translational displacement z The systems can be continuous discrete or the combination of continuous and discrete model The analyses for the axial vibrations are Undamped and Damped Natural Frequencies Calculation Steady State Forced Response Analysis The Lateral Torsional and Axial motions can be coupled through a gear mesh and thrust collar for a geared syste
119. st Bearing Temperature rise Laminar Flow Coordinates Standard Coordinates 5r Load Angle 245 Bearing Type Three Lobe K and C Coordinate Angle 0 degree Analysis Option Heat Balance Bearing Load W0 Wl x RPM w2 x RPM 2 dEB8 Convert Units English Ww 520 Wil 8 Wie 8 Axial Length L 1 25 inch Rotor Speeds Additional Speeds Joumal Dia D 1 3783 inch Start 48000 End 0 Inc 0 Brg Radial Cir 0 002 linch Lubricant Mobil DTE Light v 32 Number of Pads 3 Inlet Temperature 120 degF Bearing Data for Pad 1 Heat carried away 0 4 75 Freload 0 5454 Advanced Fetaures Trailing Edge 175 Offset 1 85 Leading Edge The bearing performance at 48 000 rpm is shown below With 120 oil inlet temperature the operating and maximum bearing temperatures 154 and 191 with laminar flow assumption BePerf 73 131 Fixed Lobe Bearing Dimensional Data Options Profile High Speed Compressor Test Bearing Temperature rise Laminar Flow L 1 25 1 3789 in Ch 0 002 in 2Cb D 0 0029 m 0 5454 tilt 0 85 Speed 48000 rpm Load 520 Lbt W LD 301 69 psi Vis 1 339 06 Reyns Sb 0 42195 E Ch 0 4761 Att 31 25 deg hmin 1 049 mils Pmax 1164 8 psi Hp 5 27196 hp 1 494 gpm T 120 154 191 degF Stiffness Lbf in 2 145 05 3 258 05 3 5970 05 9 141 0
120. st tilting pad bearings are designed such that the pivots are symmetrical with respect to the load vector 1 the load is directed onto a pad pivot or between two pivots The Pivot Angles for Load on Pivot and Load between Pivots for the Lund s Coordinate System are listed below Load between Pivots For even pads 2 4 6 8 180 Npad For small bearings the pad inertia and pivot flexibility are usually neglected For large bearings the pad inertia and pivot flexibility can reduce the bearing effective stiffness and damping significantly Several types of pad and pivot flexibility effect are included in the program They are Rigid pivot with inertia effect Spherical pivot point contact Cylindrical pivot lne contact General curvatures Constant stiffness The most commonly used tilting pad bearings are 4 pads and 5 pads bearings 4 pads tilting pad bearm 5 pads pad bearn See also Coordinate Systems Nomenclature Tilting Pad Dimensional Analysis Tilting Pad Non Dimensional Analysis 4 pads tilting pad bearing 5 pads tilting pad bearing Fixed Lobe Bearing Geometry BePerf 27 131 Tilting Pad Dimensional Analysis Table of Contents Tilting Pad Bearing Dimensional Analysis The input parameters for tilting pad bearing dimensional analysis Tilt Pad Bearing Dimensional Analysis Comment Tilting Pad Test Journal Bearing Temperature Rise Test H1 Coordinates Standard Coordinates
121. t Units Metric Axial Length L 127 ram Additional Speeds Journal Dia D 127 rnm Start 1000 End 10000 Inc 1000 Brg Radial Clr 10 0635 mm Lubricant Dynamic Viscosity 13 7895 cFoize Humber of Pads 2 Density 8 grams CC Bearing Data for Pad 1 Preload Advanced Fetaures Offset Leading Edge i 0 Trailing Edge i rd Example 2 3 Lobe Bearing Laminar and Turbulent Flow A 3 lobe bearing as shown below is used in a high speed application The load vector is directed in the middle of the lobe BePerf 72 131 DyRoBeS_BePerf C MyFolder DyRoBeS Examples Brg_3 Lobe_HeatBalance1a LDI lt Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help High Speed Compressor Test Bearing Temperature rise Laminar Flow T Bearing Data L 1 25 in Ds 1 3789 in Cb 0 002 in 2Ch D 0 0029 Cp 0 00439947 Preload 0 5454 Offset 0 85 Thetal 75 heta2 175 Load Angle 245 For Help press F1 The bearing clearance for each lobe is continuous along the circumferential direction although it is not a constant due to the preload Each lobe is identical Two cases are studied one is laminar flow and second one is turbulent flow With lammar flow assumption the input parameters are shown below with Advanced Feature OFF Fixed Pad Bearing Dimensional Analysis Comment High Speed Compressor Te
122. ta fram paz Analysis isothermal Convert Units Metric mm Mewton MPa degC cPoise gram CE Ipm rpm Jaurnal Dia D 120 1100 Axial Length L Vice 85 Density 10 85 n Brg Radial Clr Cb 01 i i Note Pad data required only when preload exists No of Recesses 4 Recess Data of Pads 8 Pad Data of Pumps i Pump Data of Loads 2 Load Data New Open Save Save Ag 2 Run Cancel Recess Pocket Data i ua and 1 1 are the adjacent recess numbers far the i th recess o di the slot if axial slot then i 1 for the 1st recess is NF Position Arc 1 bre degree a Land Depth de do le mm Pr MPa lpm Capillary Capillary Capillary Capillary BePerf 54 131 DyRoBeS BePerf C 1610 Hybrid_Carlo H J Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubriceant Flow Hydrostatic Tools wiew Help Bearing example from Carlo s report Fixed Lobe Gearing Bearing Data L 35mm Ds 79 904 mm Cb 0 066 mm 2C b D 0 0017 151 Recess Ang U Recess Arc 50 b 1 15 b ir1 15 2 Theta 55 slot 10 00 a 10mm Depth 0 65 mm Ps 12 5 MPa Hestrictar Orifice For Help press F1 Hydrostatic Hybrid Journal Bearings gt Pump Data Supply Pressure is the pressure before the Hestrickor Comment Bearing example from Carlo s repart Fixed Lobe Bearing Coordi
123. ter and the bearing 1s cylindrical When the preload has a value of 1 the shaft touches all the pads and the bearing minimum radial clearance is zero Typical preload value for a fixed lobe bearing ranges from 0 4 to 0 75 Another key parameter used to describe the preloaded bearing geometry is the fraction of converging pad length to the full arc length This parameter is called Offset or Tilt and is given by the following expression 8 81 e gt 8 4 BePerf 14 131 The value of offset is meaningful only when the bearing is preloaded At e the bearing has minimum clearance for a centered shaft and the lobe arc intersects with bearing base circle A lobe which is symmetrically located with respect to the centered journal 1e offset 0 5 is defined as having no lobe tilt and the clearance space has equal convergent and divergent arcs An offset of 0 5 is commonly used to accommodate the reversal rotation of the shaft and also to avoid the problem of the bearing being installed backwards An offset less than 0 5 increases the diverging film thickness and is not desirable Typical offset ranges from 0 5 to 1 0 For an offset halves bearing the offset could be larger than 1 depending on the position of pad center of curvature Several commonly used bearings are shown in the figures with clearance exaggerated for clarity The capability of the program is not limited to these bearings Typical Bearing Types Plain
124. ults are shown below BePerf 81 131 DyRoBeS BePerf C MyFolder DyRoBeS Examples Bre PressureDamt1c Type 8 11 Sele Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools wiew Help Dg ve Pressure Dam Bearing without relief track L 6 Ds 6 in Cb 0 005 in 2Ch D 0 00167 Cp 0 005 Preload 0 Offset 0 Theta1 10 Theta2 1 0 Pocket Arc 125 Depth 0 015 Width 4 5 Load Angle 270 Viscosity 2E 06 Reyns Density 0 03 Lbm in 3 Bearing Data For Help press F1 ai ox Fixed Lobe Bearing Dimensional Data Options Profile Pressure Dam Bearing without relief track L D 6 in Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 Speed 7000 rpm Load 3000 Lbf W LD 83 3333 psi Vis 2E 06 Reyns Sb 1 008 E Ch 0 3198 Att 80 31 deg hmin 3 401 mils Pmax 502 488 psi Hp 38 2135 hp 4 8 523 gpm Stiffness Lbf in 3 225E 06 1 042E406 J 901E 06 3 924E 06 Damping Lbf s in 6 236E 03 4 015E 03 4 010 03 1 7627E 04 Critical Journal Mass Lh 2066 BePerf 82 131 Fixed Lobe Bearing Dimensional Data Options Profile Pressure Dam Bearing without relief track L 6 in D Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 rpm 7000 E Cb 0 3198 Max Pressure 502 49 3D Pressure Profile Theta Example 4 Tapered Land Bearing A locomotive turbocharger bea
125. ure po ey See also Non Dimensional Parameters a CE WV C2 5 i p 5 T BePerf 105 131 Non Dimensional Parameters Table of Contents Non Dimensional Parameters Description Expression Sommerfeld Number Film Thickness Eccentricity Preload Offset or Pivot Ratio 22 Damping Coefficients Frictional Power Loss Critical Journal Mass where can be the pad radial clearance or bearing radial clearance See also Nomenclature BePerf 106 131 Units Units Two systems of units are provided m this program The unit conversion is listed below for reference Metric Conversions multiply Time second s second s 0000 ner baa ru a _ 0 025400 in mim imi 264 Wr 1j ae N N 4448212 Lot IN 1kg Im s _ N 88088 kof Nm 1 Nem 01128846 Lbf in Mass Lhf s fin kg 04535824 Lom ke 175 1266 Lbf srin Lori 386 088 Lhft s in Density Lhf s fin kg m kg m 2 787 S90E 04 Lbmr in kg m 1 OBBBEBE 0 7 Lbf s in giem 1 g cc 2 767990E 01 Lorin Lorwvin 0 0381273 giem Lbf s in m 0 1129846 Lhf s in VERTIT Lbffin nsi B 88475TE 3 psi kM DN i 6894757 psi OO Lbffin Mim 175 1266 Lhffin Lateral Ct bi sfin N s m M slm 175 1266 Lbf s n Torsional K bi in
126. y 12 A critical parameter affected by turbulence is the shear stress acting on the shaft U 29 C 1 0 0012 where Cfis the turbulent Couette shear stress factor For lammar flow Cf 1 The boundary conditions in the axial coordinate are that the pressure is ambient at the edges ofthe bearing pad The Swift Stieber or Reynolds boundary conditions are applied in the circumferential coordinate Film cavitation is considered and the transition boundary curve to the film rupture is determmed by iteration The governing equation for pressure distribution in a gas air lubricated journal bearing is compressible Reynolds equation 124 y a Es z U Ph Ph 12089 2 This compressible Reynolds equation is more difficult to analyze due to the existence of the pressure P in each terms compared with the incompressible flow which makes the problem non linear Weak formulation based on variational principle is applied for generating the fimte element model for the boundary value problems Since this is a nonlinear problem Newton Raphson s iterative scheme is utilized to solve the pressure increment or pressure correction BePerf 3 131 The solutions techniques for the incompressible and compressible Reynolds equation are discussed in the book Introduction to Dynamics of Rotor Bearing Systems by W J Chen and E J Gunter 2005 The BePerf program consists of seven
127. y because of their stability characteristics even though they are more expensive than fixed profile bearings The bearing is made up ofa number of pads shoes which are supported on pivots The pads are free to tilt about the pivot points to accommodate the journal motion Dynamic effects from each individual pad are assembled to obtain the full bearing performance Under Tilting Pad menu there are analysis and postprocessor for dimensional and non dimensional analyses The bearing stiffness and damping coefficients calculated from dimensional analysis can be saved as a bearing file to be readily used by DyRoBeSO Rotor All the input and output data can be viewed fromthe Text Output option while only the key output parameters are summarized in the Tabulated List and can be displayed m the graphic forms Tilting Pad Bearing Geometry Parameters used to describe the bearing geometry are defined in this section Tilting Pad Dimensional Analysis The dimensional analysis includes Constant Viscosity analysis and Heat Balance analysis For Constant Viscosity analysis user must input a lubricant dynamic viscosity and no temperature rise will be calculated For Heat Balance analysis user must select a lubricant type and input the lubricant inlet temperature Supplied oil flow rate can also be entered if it is known Otherwise the side leakage flow will be used in the heat balance calculation The operating and maximum film temperatures will be calcu
128. yFolder DyRoBeS xample WePerfibre_PressureDamia Kef Project Fixed Lobe Tiling Pad Floating Ring Gas Brg Thrust Lubricant Flow wiew Help Pressure Dam Bearing with center relief track Bearing Data Pocket L 6in Ds 6 in Cb 0 005 in FCD 0 00167 Cp 0 005 in Preload 6 Offset 0 Theta1 10 Theta 170 Pocket Are 125 Depth 0 015 Width 4 5 Relief Width 1 Load Angle 276 Viscosity 2E 06 Density 0 03 For Help press F1 Pressure Dam Bearing with center relief track 6 in D Cb 0 005 in 2Cb D 0 00167 Max C 0 02000 Min C 0 00500 Relief Track 3D FEA Mesh Data Theta BePerf 77 131 The pressure dam bearing has discontinuity in the bearing clearance Therefore the Advanced Feature must be turned ON Additional data for the pocket and relief track are entered in the Advanced Feature dialog box The computer program allows for the pocket and relieftrack in a preloaded lobe although typically they are in a plain lobe without any preload Note that the pocket axial length PocketAxL must be smaller than the bearing axial length in order to have a pocket with side dams If PocketAxL equals to the bearing axial length then it becomes a step bearing without side lands which is acceptable in this program The pocket and relief track cannot co exist Fixed Pad Bearing Dimensional Analysis Comment Pressure Dam Bearing with center relief track Coordinates Standard Coordinates s r
129. yFolder DyRoBeS Examples Bre PressureDam1b Type _ 8 101 Sele Project Fixed Lobe Tilting Pad Floating Ring Gas Brg Thrust Lubricant Flow Tools View Help z Pressure Dam Bearing with side relief track Bearing Data L 6 Ds 6 in Cb 0 005 in 2ZCb D 0 00167 Cp 0 005 Preload 0 Offset 0 Theta1 10 Theta2 1 0 Pocket Arc 125 Depth 0 015 Width 4 5 2 Side Relief 1 Load Angle 270 Viscosity 7E 06 Reyns Density 0 03 Lbm in 3 For Help press F1 The bearing performance and pressure distribution are shown below BePerf 80 131 Fixed Lobe Bearing Dimensional Data Options Profile Pressure Dam Bearing with side relief track 6 in D 6 in Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 Speed 7000 rpm Load 3000 Lbf W LD 83 3333 psi Vis 2E 06 Reyns Sb 1 008 E Ch 0 3985 Att 71 03 deg hmin 3 008 mils Fmax 5 7 909 psi Hp 35 2312 hp 4 9 073 gpm Stiffness Lbf in 3 315E 06 38 677E405 5 549E 06 3 835 06 Damping Lbf siin 6 0 4E 03 4 321E 03 4 317 03 1479E 04 Critical Journal Mass Lb 8659 5 Fixed Lobe Bearing Dimensional Data Sele Options Profile Pressure Dam Bearing with side relief track L 6 in D Cb 0 005 in 2Cb D 0 00167 m 0 tilt 0 rpm 7000 E Cb 0 3985 Max Pressure 577 91 3D Pressure Profile Theta When ReliefAxL equals to zero then no relief track is applied The res
130. yed versus Sommerfeld Number and the dimensional results are displayed versus shaft speed The units used in the dimensional results are discussed in Chapter Units DyRoBeS also provides a large number of postprocessing tools for graphically displaying the results You can open the Child Windows PostProcessor graphics as many as you like to help you to interpret and understand the analysis results When you open a postprocessing Child Window some default initial settings are used to display the results To modify these settings select the Settings under the Options to make necessary changes The functions available in the PostProcessor are described below Redraw allows you to redraw the Child Window and refresh the picture Settings allows you to modify the default graphic settings to suit for your need Print allows you to get a hard copy of the graph Normalization allows you to display the results normalized with respect to Cp or Cb Profile allows you to select the pressure profile at different shaft speed for dimensional analysis or eccentricity ratio for non dimensional analysis For 3D pressure profile plot the Advanced Features must be checked ON in the input See also Fixed Lobe Dimensional Analysis Fixed Lobe Non Dimensional Analysis Tilting Pad Dimensional Analysis Tilting Pad Non Dimensional Analysis Non Dimensional Parameters Nomenclature Examples E Tilting Pad Bearing Non Dimensional Data tenes Normalizatio

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