稀薄效应对径向气体轴承承载性能的影响

Influence of gas rarefaction effect on load capacity performance of gas-lubricated journal bearings

基于超薄气膜润滑理论,通过引入微尺度条件下气体稀薄效应流量因子,推导考虑稀薄效应的气体润滑轴承雷诺方程,并采用有限差分法对其进行离散求解,数值分析了不同偏心率、半径间隙以及转速对气膜压力分布、承载力的影响规律,并与未考虑稀薄效应的数值结果进行比较。结果表明:稀薄效应的存在并不会影响压力分布规律,其中气膜压力分布具有非线性,并沿着轴向呈抛物线状;最大压力及承载力随转速和偏心率的增大而增大,随着半径间隙的增大而减小;当考虑气体稀薄效应时,气膜各点压力水平及承载力相比于未考虑时有所下降;当半径间隙越小,偏心率越大时,气体稀薄效应越显著,最大压力及承载力的变化幅度也越明显。

Based on the theory of the molecular gas-film lubrication, the Reynolds equation of the gas bearing was deduced through introducing flow factor of the rarefaction effect under the micro-scale condition, and was dissociated by using the finite difference method. The influence of different eccentricity, radius gap and speed on the pressure distribution and bearing capacity was numerically analyzed and compared with the numerical results without the rarefaction effect. The results show that the presence of the rarefaction effect does not affect the pressure distribution, in which the pressure distribution is non-linear and para- bolic along the axial direction. The maximum pressure and bearing capacity increase with the increase of speed and eccentricity, and decrease with the increase of radius gap. When considering the rarefaction effect, the pressure and bearing capacity are lower. When the radius gap is smaller and the eccentricity is larger, the rarefaction effect is more significant, and the change of maximum pressure and bearing ca- pacity is more obvious.