滑移边界对微型气浮轴承稳态性能的影响

根据气膜厚度的Knudsen数,确定滑移流为微型气浮轴承内部的润滑机制。引入二阶滑移流边界条件对连续流的状态方程进行修改,得到滑移流机制下修正的雷诺方程。利用有限差分法对雷诺方程求解,得到两种情况下的气压分布,进而得到相应的承载能力和偏位角。经过对比分析,发现在滑移流机制下气浮轴承的力学性能与连续流机制的情况有较大差异。在相同的转速和偏心率下,滑移流效应降低了气压分布的曲率,进而降低了气浮轴承所能够提供的承载能力。

EFFECTS OF SLIP FLOW ON STEADY PERFORMANCE OF MICRO GAS BEARING

Judging with Knudsen number, the flow regime in the micro gas bearing is slip regime instead of the continuum regime. The second-order slip model is adopted and the modified Reynold's equation for the gas flow is gotten. Solving the Reynold's equations with the finite difference method (FDM), the gas pressure distributions of continuum flow regime and slip regime are obtained. Consequently, the dimensionless load carrying capacities and attitude angles are acquired. Comparing the solutions between two regimes, it shows that there are distinct discrepancies between the steady performances of the two regimes. At the same rotating speed and eccentricity ratio, the slip effect reduce the gas pressure curvature and hence the load carrying capacity.