Research On Turbulent Lubrication Performance Of Journal Bearing With High Speed,Heavy Load,and Low Viscosity Lubricant

High-speed journal bearings have been widely used in turbine generator sets,gas turbines,industrial steam turbines,blowers,compressors and centrifuges,and other industrial equipment.The analysis of the turbulent lubrication of journal bearings plays an important role in the design of high-speed journal bearings.However,the current research on bearing turbulent lubrication performance under the influence of practical factors has problems such as comprehensiveness and rationality.To comprehensively and accurately grasp the turbulent lubrication of journal bearings under actual operating conditions.This paper takes the rough surface journal bearings as the research object and researches turbulent lubrication of bearings under the comprehensive influence of multiple factors.(1)The stochastic method and the average flow method were used to establish a random turbulent lubrication model and average flow turbulent lubrication model for rough surface bearings considering the influence of surface topography.The correctness of the proposed models was verified by comparison with the experimental results in literature.(2)The turbulent lubrication performance of journal bearings with rough surface was analyzed based on the average flow turbulent lubrication model.The finite difference method was used to solve the corresponding average flow turbulence lubrication model equation.The results show that when the bearing's nominal eccentricity ratio is large,the changes in bearing surface orientation parameters and the root mean square value of the dimensionless journal and bearing surface roughness have a significant effect on the dimensionless maximum film pressure and dimensionless load capacity.At the same nominal mean Reynolds number,changes in bearing surface orientation parameters and dimensionless bearing surface roughness have a significant effect on the dimensionless maximum film pressure and dimensionless load capacity.(3)The turbulent lubrication performance of journal bearings with rough surface under the influence of thermal effects was analyzed based on the average flow turbulent lubrication model equation,energy equation,and lubricant viscosity-temperature equation of lubricant.The finite difference method was used to solve the corresponding average flow turbulence lubrication model equation,energy equation and viscosity-temperature equation.The results show that at the same nominal eccentricityratio or nominal average Reynolds number,compared with bearings without considering thermal effects,the dimensionless maximum film pressure,dimensionless load capacity and dimensionless frictional power of bearings with thermal effects are reduced,the dimensionless maximum film temperature and dimensionless side leakage of bearings with thermal effects are increased.(4)The modified film thickness equation was used to establish an analysis method of journal bearings with rough surface considering the influence of journal misalignment.And the turbulent lubrication performance of the journal bearing with rough surface under the influence of journal misalignment was analyzed.The results show that when the journal is misaligned,as the nominal eccentricity ratio of the central section of the bearing increases,the dimensionless maximum film pressure,dimensionless load capacity,dimensionless frictional power,dimensionless side leakage and dimensionless misalignment moment increased.At the same nominal average Reynolds number of the bearing,as the degree of journal misalignment increases,the dimensionless maximum film pressure,dimensionless maximum film temperature,dimensionless load capacity,and dimensionless misalignment moment increase.(5)The turbulent lubrication equation of the rough surface journal bearing considering the axial movement of the journal is established with the use of the coordinate transformation method.The turbulent lubrication performance of the rough surface journal bearing under the influence of the axial movement of the journal is analyzed.The results show that with the increase of the axial movement velocity of the journal,the nominal average Reynolds number,the maximum average film pressure,the maximum film temperature,the load capacity,the friction power,and the side leakage increase.(6)Theoretical analysis and experiment on the turbulent lubrication performance of the journal bearing of the aviation engine fuel pump are carried out.