考虑稀薄气体效应的止推箔片轴承静特性分析

以波箔型气体止推箔片轴承为研究对象,基于1阶滑移速度边界条件,建立了考虑稀薄气体系数的修正雷诺方程.结合Newton-Raphson迭代法和有限差分法,耦合求解Reynolds方程和润滑膜厚度方程,仿真获得了止推箔片轴承的轴向承载力、起飞转速等静态性能,并研究了稀薄气体效应和轴承结构参数对止推箔片轴承静态特性的影响.结果表明:稀薄气体效应将使止推箔片轴承的轴向承载力减小,起飞转速增大,且稀薄气体效应的影响随轴承工作转速、箔片变形柔度系数的提高有所减弱;止推箔片轴承的安装间隙小于10μm时,起飞转速随安装间隙的减小急剧增大,因而在止推箔片轴承装配时须严格控制轴向间隙. 

Static characteristics analysis of foil thrust bearing considering the rarefield gas effect

A modified Reynolds equation considering the rarefield gas coefficient for the bump type gas foil thrust bearing was established based on the first-order slip velocity boundary condition. The coupled modified Reynolds and lubricating film thickness equations were solved using Newton-Raphson iterative method and finite deference method. The static characteristics including axial load capacity and lift-off speed were obtained. The effects of rarefied gas and bearing structural parameters on the static characteristics were analyzed and discussed. The results indicate that with the influence of rarefield gas, the axial load capacity decreases, and the lift-off speed increases. And the rarefield gas has a slighter effect under a higher operating speed and a larger foil compliance coefficient. When the assembled clearance is smaller than 10 μm, the lift-off speed increases rapidly with increasing of the assembled clearance of the foil thrust bearing. Therefore, the axial clearance should be controlled carefully in assembling the foil thrust bearing.