新型三瓣式径向气体箔片动压轴承热特性分析

Thermal Characteristic Analysis of Novel Three-pad Radial Gas Foil Hydrodynamic Bearings

为研究新型三瓣式径向气体箔片动压轴承的温度特性,提出了考虑热特性的润滑理论计算模型.通过耦合求解非等温Reynolds方程和气膜能量方程,并计入转子的离心效应和热膨胀量对轴承间隙的影响,运用数值模拟的方法求解出轴承内气膜温度分布,研究轴承载荷、转速和冷却气流量等因素对轴承温度的影响.计算结果表明:气膜温度峰值位于压力峰值的下游位置;气膜温度随轴承载荷和转子转速的增加而递增,相较于转速对气膜温度的影响,轴承载荷的影响并不明显;往轴承箔片结构内通入冷却气流可以起到明显的降温效果,且轴承温度随冷却气流的上升先迅速下降后逐渐平缓.

A lubrication theoretical calculation model of thermal characteristic is proposed to study the temperature characteristics of a novel three-pad radial gas foil hydrodynamic bearing.The numerical simulation method is used to calculate the film temperature distribution of the gas foil bearing by coupling the non-isothermal Reynolds equation and the energy equation,and the effects of the rotor thermal expansion and the rotor centrifugal expansion on the bearing clearance are taken into account.The effects of the bearing load,speed and cooling gas flow on bearing temperature are analyzed.The results show that the peak temperature of the film is located at the downstream of peak pressure;the air film temperature increases with the rise of bearing load and rotor speed,and the results indicate that the rotational speed has a larger effect on the bearing temperature than the bearing load;the cooling effect of the airflow is obvious,and the bearing temperature decreases rapidly with the rise of the cooling airflow and then gradually calms down.