Study On Dynamic Stability Of Gas Film Based On CFD Spherical Hydrostatic Bearings

With the rapid development of high-speed rotating machinery and precision instruments,gas lubricated bearings with its unique characteristics are gradually being recognized and attention.Compared with the traditional lubricating bearings,the advantages of gas lubricated bearings is very obvious,such as small noise,friction loss is small,does not produce heat,vibration,long life,can work in a special environment and so on.Hydrostatic mixed gas bearing combines the advantages of dynamic pressure bearing and hydrostatic bearing,and using the static pressure bearing gas supply way to avoid the solid contact between the bearings in the start and stop phase,while stop the external gas supply in the high-speed rotation,and use the dynamic pressure bearing capacity,which greatly reduced power consumption.As the maximum speed of static and dynamic gas bearings can reach hundreds of thousands of revolutions per minute,the bearing characteristics of the film changes a very complex nonlinear random process,and bearing the film characteristics directly affect the bearing rotor movement,so the bearing The study of gas film is the key to study the bearing stability.In this paper,Spherical Groove Hydrostatic Bearing is taken as the research object,using the method of spherical coordinate system in PROE software,a threedimensional gas film model of spherical spiral groove hydrostatic bearing is established,based on CFD technology and FLUENT software,the three-dimensional gas film model is processed into a finite element model of lubrication analysis.The effects of bearing groove width ratio,groove depth ratio,helix angle and groove number on the bearing pressure and bearing capacity of bearing are revealed.And based on this,the structural parameters of the bearing are optimized.On the basis of steady state calculation,the 6 DOF passive grid computing module in FLUENT software is applied,the simulation analysis of the dynamic process of Spherical Groove Hydrostatic Bearing under dynamic operation is carried out.Through the study of the bearing in the process of the axis of the track map,spectrum,revealed the various states of the bearing from stable operation to the instability,and Select the bearing in different motion state,the special point of the speed,force and displacement changes,calculate the bearing at this time the stiffness,damping coefficient,in order to establish the bearing movement state and stiffness,damping coefficient of the link between,and based on the stiffness and damping coefficient,the structural parameters of the bearing are further optimized.