小孔节流空气静压止推轴承节流孔出口流场特性研究

Research on Orifice Exit Flow Field Characteristics of Aerostatic Bearings with Small Hole Throttle

小孔节流空气静压轴承一般都采用数值方法进行分析,数值方法求解过程中一般采用简化的N-S方程求解,不能真实反映节流孔出口流场的真实特性。研究小孔节流形式的空气静压止推轴承的流场特性,建立小孔节流空气静压轴承模型,应用流体分析软件求解完整N-S方程,并加入湍流模型求解,使计算结果更加准确。计算结果表明,气体流出节流孔后压力骤降且可能出现负压,压力骤降的值和气膜间隙成正比;在节流孔出口附近,气膜上下边界的空气流速小于气膜中间的流速,而且气体易与气膜上边界产生速度分离。

The research of small hole throttle aerostatic bearing commonly uses the numerical analysis method to solve the simplified Navier-Stokes equation, which can not reflect the actual characteristics of the orifice exit flow field. The flow field characteristics of small orifice air static pressure thrust hearing were studied, and the small orifice air static pressure bearing model was set up. By using fluid analysis software to solve the full Navier-Stokes equations and using the turbulence model, the more accurate calculation resuhs were obtained. The calculation results show that the pressure drops rapidly and negative pressure may occur after the gas flow out of the throttle orifice, and the value of pressure drop is proportional to the gas film clearance. Near the orifice exit, the air flow rate of the gas film upper and lower boundary is less than that of the gas film middle, and the gas is easy to be separated from the gas film upper boundary.