计入热变形影响的内燃机主轴承热流体动力润滑分析

THERMO-HYDRODYNAMIC LUBRICATION ANALYSIS OF INTERNAL COMBUSTION ENGINE'S MAIN BEARING CONSIDERING THERMAL DEFORMATION EFFECTS

根据动载滑动轴承热流体动力润滑理论,结合热变形矩阵法,提出一种考虑热变形因素影响时的内燃机主轴承热流体动力润滑分析方法,阐述该方法的基本理论和控制方程,探讨热变形因素对主轴承工作时的轴心轨迹、润滑油流量、最大油膜压力和最小油膜厚度等状态参量的影响情况。结合一主轴承实例进行数值仿真分析,仿真分析结果发现,计入热变形影响因素后,同未考虑热变形影响时分析得到的结果相比,轴心运动轨迹发生了很大变化,平均润滑油流量和一个载荷周期内的最大油膜压力均明显增加,一个载荷周期内的最小油膜厚度明显减小,润滑油平均温升则稍有减小。内燃机主轴承在工作时受各种热源因素的影响会产生热变形,在主轴承设计以及内燃机润滑系统供油量设计过程中考虑这种变形因素的影响是很有必要的。

Based on the thermohydrodynamic lubrication theory of dynamically loaded bearing, researches on the lubrication of internal combustion engine（ICE）＇s main bearing considering thermal deformation effects are presented combining with thermal deformation matrix method. Basic theory and governing equations adopted here are described. Influences on main beating＇s lubrication performance from thermal deformation are also discussed here, such as on journal orbit, oil flow rate, maximum film pressure and minimum film thickness, etc. A simulation analysis example with ICE＇s main bearing is presented. Simulation results show that the orbit of journal has a large change with considering thermal deformation effects. And the average flow rate and maximum film pressure in one load cycle are increased evidently. While the minimum film thickness in one load cycle is decreased distinctly. The rise of oil temperature in one load cycle has just a little change. It points out that, thermal deformation will appear in ICE＇s main bearing when it works due to many kinds of heat factors and this deformation should be considered seriously in the design of main bearing and ICE＇s lubrication system.