基于滑移流模型的微型箔片轴承倾斜性能研究

针对传统连续模型未考虑气流滑移效应的影响,而无法准确描述微小间隙下气膜压力分布的问题,在一阶滑移和Wu滑移速度边界条件基础上建立微型气体止推箔片轴承在倾斜状态下的修正雷诺方程,并使用有限体积法求解获得在不同倾斜角度、不同箔片变形柔度系数、不同转速和不同最小气膜间隙条件下的微型止推箔片轴承的气膜压力分布和轴向承载力,同时分析各种模型在不同结构参数下的差异。计算结果表明:微小间隙倾斜条件下气流滑移对轴承承载力影响较大。一阶滑移修正及Wu新滑移修正模型获得的承载力明显低于连续模型。模型间的结果偏差随倾斜角度、轴承转速和轴承最小间隙的减小而逐渐增大。因此连续模型已不适用于此条件下的分析,为得到更精确的精密磨削机床设备的参量特性,应使用更贴合实际的滑移修正模型进行计算。

Research on Tilt Performance of Micro-foil Bearing Based on Slip Flow Model

Because the traditional continuous model does not consider the effect of airflow slip, it can not accurately describe gas film pressure distribution at a small clearances. In this paper, based on the first-order slip and Wu slip velocity boundary conditions, we established a modified Reynolds equation for gas thrust foil bearings at inclined state. Resulting equation is solved by a finite volume method under different inclined angles, different deformable compliance coefficients and different deformations of the foils. The film pressure distribution and axial bearing capacity of micro thrust foil bearings at different rotational speeds and minimum film clearances are analyzed, and the differences among three models under different structural parameters are studied. Our results show that the air slip has a great influence on bearing capacity under inclined condition. The pressure and load-carrying capacity of the first-order slip correction model and Wu's new slip correction model are apparently lower than those of the continuous model. The deviation between the results of the models increases with the decrease of inclination angle, bearing speed and the minimum clearance. In conclusion, the continuous model is no longer suitable for the analysis under this condition, a more accurate slip correction model should be used, in order to obtain more accurate parameters of precision grinding machine tools.