高压圆盘气体轴承可压缩边界层形态分析

Analysis of compressible boundary layer pattern of high pressure circular gas bearing

高压圆盘气体轴承中气流速度高、雷诺数大,气膜内边界层的发展形态对主流和轴承承载力的影响不可忽视。在数值计算方法可行性验证的基础上,采用γ-Reθ转捩模型对具有双对称收缩段结构的高压圆盘气体轴承气膜内的流场进行数值求解,分析气膜间隙、供气压力及轴承半径对气膜边界层的影响。结果表明,减小气膜间隙、降低供气压力、增大轴承半径,均可促进气膜边界层的发展;边界层完全发展后,主流被边界层淹没,边界层内的黏性力作用于气流,气流速度下降,使气膜内的压力维持在较高水平,从而提高了气体轴承的承载能力。根据数值计算结果确定了高压圆盘气体轴承实验模型的工作参数。

In the high pressure circular gas bearing,airflow velocity is high and Reynolds number is large,so the impact of development pattern of boundary layer in the gas film on the mainstream and bearing＇s load carrying capacity cannot be ignored.Based on the feasibility of numerical calculation method,which was validated,γ-Reθtransition model was used to numerically solve the flow field in the gas film of high pressure circular gas bearing with disymmetric contraction cone,then the influences of gas film clearance,gas inlet pressure and bearing radius on the boundary layer of gas film were analyzed.The results show that decreasing gas film clearance and gas inlet pressure as well as increasing bearing radius can promote the development of gas film boundary layer;the mainstream is submerged by the boundary layer which has been fully developed,and the viscous force in the boundary layer acts on the airflow,causing the decline in airflow velocity and keeping the pressure in the gas film at a high level,thereby the load carrying capacity of the gas bearing is improved.According to the numerical calculation results,the working parameters of experimental model of high pressure circular gas bearing are determined.