耦合CFD径向微动分析的航空齿轮泵轴承起动瞬时润滑特性研究

In order to solve the lubrication problem of oil film inside an aero gear pump gear-shaft/bearing gap during dynamical start-up process, on the basis of gear pump CFD simulation, axis center radial micro-motion analysis coupled with CFD has been carried out based on dynamic relationship between gear shaft load and lubrication gap mixed supporting effects. Numerical analysis was carried out to investigate the start-up transient lubrication characteristics and contact behavior of journal bearings under gear pump transient field influence. The results show that: the load fluctuation caused by gear pump transient field variation has a more noticeable effect on pump shaft motion at low eccentricity position during startup than other cases. Note that difference of final static equilibrium position caused by load fluctuation are 0.43% and 7.29% on different directions. Besides, the influence of micro-characteristic on surfaces mainly exists in high eccentricity state during startup. Under the same condition of inlet pressure, increase trend of pump outlet pressure has no change to asperity contact time but makes contact more serious. It yields a decrease in contact time and difference between different directions contact forces as rotate speed increases. Regarding for the oil film characteristics in lubrication gap, the variation of minimum film thickness under different pump operating conditions is similar to center trajectory. When the outlet pressure increases from 3.02MPa to 9.1MPa, the maximum reduction rate of the minimum film thickness approaches 26.32% and 101.43%.