Research On The Performance Of Turbulent Lubricated Hydrodynamic And Static Pressure Gas Radial Sliding Bearings

Gas-lubricated bearings are widely used in precision and even high-precision machines in the aerospace,electronics,medical,and defense industries because of their high speed,high precision,low power consumption,and long life.The gas hybrid journal bearings is a kind of bearing that combines the hydrostatic bearing and the hydrodynamic journal bearing,which has the advantages of both,and can avoid the disadvantages of both.For high-speed,large-diameter gas hybrid journal bearings,the fluid state of the bearing gap film may be turbulent.In this paper,the gas hybrid journal bearings is taken as the research object,and the dynamic and static performances of laminar lubrication and turbulent lubrication gas hybrid journal bearings are studied respectively,in order to obtain the nearest practical calculation results and obtain the best performance.The working condition parameters and structural parameters are used to provide theoretical basis and practical reference value for further research and practical application of turbulent lubricating gas hybrid journal bearings.(1)This paper summarizes the judgment basis of laminar flow and turbulent motion of hydrostatic bearing fluids;(2)Considering the gas as an ideal gas,a mathematical model of the turbulent lubricating gas hybrid journal bearings is established,and the turbulence influence coefficient is introduced into the compressible fluid Reynolds equation.(3)Based on the finite difference method,the MATLAB software is used to solve the compressible gas Reynolds equation and the modified compressible Reynolds equation with turbulence factor.The dynamic and static characteristics of the dynamic and static gas hybrid journal bearings are analyzed.The results show that the static characteristics of continuous Slot-restriction laminar flow lubrication and turbulent lubrication dynamic and static gas hybrid journal bearings are better than discontinuous Slot-restrictions;the eccentricity,length to diameter ratio,rotational speed and supply pressure have significant effects on the static performance of the bearing.The eccentricity,the rotational speed and the supply pressure have a significant influence on the dynamic performance of the bearing;the large eccentricityand the higher rotational speed can make the laminar flow lubrication and the turbulent lubrication dynamic and static gas radial sliding bearing have better dynamic performance.(4)Using the Fluent software to simulate the dynamic and static gas radial sliding bearings of the k-e turbulence model.The results show that the deviation of the calculation results obtained by the two methods is small,which indicates that the method of solving the compressible gas Reynolds equation and the improved compressible Reynolds equation with turbulence factor is applicable.The calculation results are verified from the side.The results of this paper show that for the gas hybrid journal bearings of turbulent lubrication,when the bearing length to diameter ratio L/D ? 0.7,the static stiffness of the discontinuous Slot-restriction bearing is greater than that of the continuous Slot-restriction bearing,taking into account the dynamic characteristics of the bearing.The turbulent lubrication gas hybrid journal bearings speed is preferably 40,000 rpm to 56,000 rpm,the eccentricity is preferably 0.3 ? ? ? 0.6,the number of slots is 6 to 12 is the best,and the length to diameter ratio is preferably 1.8 ? 2.2.