线接触弹流润滑最小油膜厚度综合对比分析

General Analysis of Minimum Film Thickness in Line Contact Elastohydrodynamic Lubrication

关键词:  航空发动机  线接触  油膜厚度  弹流润滑  热效应

Key words:  Aeroengine  Line contact  Film thickness  Elastohydrodynamic lubrication  Thermal effect

摘要:

针对航空发动机中某直齿轮节圆位置，考虑弹流润滑中的热效应，研究了速度参数（uˉ），载荷参数（wˉ）与材料参数（gˉ）对等温解与热解的影响。并对目前广泛用于计算等温条件下最小油膜厚度的三种经验公式进行了对比分析。发现在本文研究的工况范围内采用Грубин与Dowson公式计算得到的弹流润滑等温解与热解误差较大。而Yang公式在速度参数较低或载荷参数适中的情况下等温解与热解误差较小，在部分工况中可以直接采用该公式对线接触最小油膜厚度进行预测。三种等温经验公式均将载荷参数的影响估计过高。同时以相对误差10%作为量化等温解与热解的界限给出了各无量纲参数的参考范围，若满足以下条件之一，则不可忽略弹流润滑中热效应的影响，等温解不再适用：（1）uˉ>10^-10；（2）wˉ<5×10^-5且uˉ>5×10^-11；（3）wˉ>3×10^-4。

Abstract:

Aiming at the pitch circle position of a spur gear in an aeroengine， considering the thermal effect of elastohydrodynamic lubrication， the effects of velocity parameters （uˉ）， load parameters （wˉ） and material parameters （gˉ） on isothermal solution and thermal solution were studied. Three empirical formulas widely used to calculate the minimum oil film thickness under isothermal conditions are compared and analyzed. It is found that the error between the isothermal solution and thermal of elastohydrodynamic lubrication calculated by the formula of Грубин and Dowson is large within the working conditions studied in this paper. Yang’s formula has a small error in isothermal solution and thermal solution under low velocity or moderate load parameters， which can be directly used to predict the minimum oil film thickness of line contact in some working conditions. All three isotherm empirical formulas overestimate the effect of load parameters. The relative error of 10% is taken as the boundary between the quantized isothermal solution and thermal solution， and the reference range of each dimensionless parameter is given. If one of the following conditions is met， the influence of thermal effects in elastohydrodynamic lubrication cannot be ignored， and the isothermal solution is no longer applicable： （1） uˉ>10^-10； （2） wˉ <5×5^-10 and uˉ >5×10^-11； （3） wˉ >3×10^-4.