ROMAC油膜轴承程序及试验台介绍PPT文件格式下载.pptx

1、,Paul Allaire,Ph.D.Mac Wade Prof.,University of VirginiaAmir YounanROMAC Software FellowTim Dimond ROMAC Test Rig Fellow,1,Fluid Film Bearing Software and Test Rig,Viscous shearing:#friction between different layers of fluid particles,Fundamental Physics（Hydrodynamic,Steady State）,2,Fluid Film Beari

2、ng Software and Test Rig,Steady state load capacity（Hydrodynamic pressure）,Moving surfaceViscous fluidConverging wedge,3,Fluid Film Bearing Software and Test Rig,Fundamental Physics（Hydrodynamic,Steady State）,4,Fixed geometry:#external load is vertical,but the journal moves both,vertically and horiz

3、ontally,indicating,Fundamental Physics（Hydrodynamic,Steady State）,Tilting pad:#external load is vertical,and the journal moves almost purely vertically,indicating minimum cross-,large cross-coupling.Fluid Film Bearing Software and TecstoRuigpling.,Interactions between various aspects,What needs to b

4、e modeled?#,Fluid Film Bearing Software and Test Rig,5,A good bearing code should model all those aspects!#,Hydrodynamic bearingJournal（radial）bearings,Fluid Film Bearing Software and Test Rig,6,THBRGTHPAD,（fixed geometry journal bearing）（tilting pad journal bearing）,MAXBRG（All journal bearing）Thrus

5、t bearingsTHRUSTHydrostatic bearingJournal（radial）bearingsHYDROBRG,Bearing analysis,Fluid Film Bearing Software and Test Rig,7,PressureTemperatureDeformationsTurbulenceMoreNumerical methodFinite Element Method,ROMAC developed several computer codes to analyze fluid film journal bearingsEach code hav

6、e different capabilities and accuracyHowever,they share similar input and output parametersProgram inputGeometry（diameter,clearance,preload,length,）Lubricant（viscosity,specific heat,）Operating condition（speed,load,）Modeling options（adiabatic or with condition,various deformations,）,Fluid Film Bearin

7、g Software and Test Rig,8,ROMAC Journal Bearing Codes,Program outputEquilibrium position（eccentricity and attitude angle）Maximum Babbitt temperatureJournal temperatureMaximum pressureMinimum film thicknessFlow ratesFriction power lossStiffness and damping coefficientsRigid rotor stability threshold

8、speed,Fluid Film Bearing Software and Test Rig,9,ROMAC Journal Bearing Codes,THBRG,Fluid Film Bearing Software and Test Rig,10,Hydrodynamic journal bearing codeFixed geometry designsPlain journal,elliptical,offset,two axial groove and multi-lobe bearingsFlooded oil feed conditionTemperature effects

9、includedLaminar and turbulent flows1-D numericalAssume axial pressure profilesAssumed axial and radial temperature profilesFast to run!#,ROMAC Journal Bearing Codes,11,THBRG Steady State Properties and Dynamic Coefficients,Oil Film Dynamic Forces:#Linear Model,Represent oil film as a group of spring

10、s and dampers,At each point in time,forces become,This linear model with its stiffness and damping coefficients forms the basis of rotordynamic designCross-coupling is quantified by the cross-coupled stiffness coefficients KxyKyx,THPAD,Fluid Film Bearing Software and Test Rig,12,Hydrodynamic journal

11、 bearing codeConventional tilting pad designsFlooded oil feed conditionTemperature effects includedVarious deformations includedLaminar and turbulent flows1-D numericalAssume axial pressure profilesAssumed axial and radial temperature profilesFast to run!#,ROMAC Journal Bearing Codes,Comparison of T

12、ilt Pad Brg K,C To Measured Values,Fluid Film Bearing Software and Test Rig,13,THBRG and THPAD use the same basic theories and numerical methodsThey were industrial standard and have been successfully used by ROMAC members for many yearsThey are computationally very efficient and still widely used t

13、odayTo further expand capability and improve accuracy,the new generation of ROMAC journal bearing code was developedMAXBRG,ROMAC Journal Bearing Codes,Fluid Film Bearing Software and Test Rig,14,MAXBRG,Fluid Film Bearing Software and Test Rig,15,Bearing designsFixed geometry bearings（also THBRG）Plai

14、n journal,elliptical,offset,two axial groove and multi-lobe bearingsConventional tilting pad bearings（also THPAD）Pressure dam bearingsDirectly lubricated bearings（inlet groove and spray bar）Oil feed conditionsFlooded（also THBRG and THPAD）High ambient pressureAxial flow Starvation Oil Ring,ROMAC Jour

15、nal Bearing Codes,Advanced theories used by MAXBRG,Fluid Film Bearing Software and Test Rig,16,2-D finite element method for the pressure and temperature2-D plain strain finite element model for pad deformationsTurbulence model fine-tuned using CFD approachNew theory for direct lubricationNew models

16、 for starvationCoupled film-pad approach leading to robust temperature computation,ROMAC Journal Bearing Codes,Fixed Geometry Journal Bearing,17,Pressure Dam Journal bearing,Journal Bearing Type:#,Tilting Pad Journal bearingFluid Film Bearing Software and Test Rig,Theoretical Modeling Film Temperature,2-D approximation w/conductionAssume constant axial temperature（2-D in x and y）Acceptable for flooded flow condition Not good foraxial flowhigh ambient pressureUnsmooth padMisaligned shaft,x:#circumferential