微气体螺旋槽推力轴承转子系统非线性动力学分析

Analysis of Nonlinear Dynamic for Micro Gas Lubricated Spiral Groove Thrust Bearing-Rotor System

基于分子气体膜润滑模型探讨微气体螺旋槽推力轴承中的稀薄效应,将广义雷诺方程与运动学方程在时域内耦合并采用直接数值模拟方法联立求解,获得了任意时刻微转子的瞬态位移和速度响应,考察了气体稀薄效应以及不同螺旋槽结构参数对微气体螺旋槽推力轴承-转子系统非线性动力学行为的影响,并得到不同转速对应的轴向扰动临界值.结果表明:考虑稀薄效应时微轴承-转子系统显示出更好的稳定性;转速增加,轴向扰动临界值降低;能提高微轴承承载力的最佳螺旋槽结构参数,并不利于提高微系统的稳定性.

The molecular gas film lubrication model was employed to study the ettect ot rarefaction in the micro gas spiral groove thrust bearing. The generalized Reynolds equation and the kinetic equation were coupled in the time domain and solved simultaneously by the direct numerical method, and then the transient displacement and transient velocity of the micro rotor at any time were obtained. The effects of gas rarefaction and the spiral groove parameters on the nonlinear dynamic behavior of micro gas lubricated spiral groove thrust bearing-rotor system were investigated, and the critical values of axial disturbance corresponding to the different rotation speeds were further obtained. The results show that the micro bearing-rotor system presents better stability when the gas rarefaction is considered. The higher the rotational speedis, the lower the critical value of axial disturbance becomes. It is also shown that the optimum spiral groove parameters for enhancing the micro-bearing load capacity are not beneficial for the system stability.