活塞裙润滑油膜温度场有限元分析

Analysis of Temperature Field of Lubrication Oil Film of Piston Skirt by Finite Element Method

利用八节点等参有限单元法,对活塞裙的润滑油膜进行了温度场分析。首先给出了活塞裙的雷诺润滑方程、二阶运动方程以及油膜的能量方程。然后在给出上述方程的有限元求解表达式和步骤的基础上,对它们进行了联立求解。最后以某发动机为例,研究了其活塞裙部润滑油膜温度场在发动机运转周期内的变化。计算结果表明,油膜温度场随曲柄转角的变化而变化;活塞在上止点时,油膜温度从活塞裙上端到下端基本呈递减趋势;活塞位于行程中部时,在靠近活塞裙上端附近,出现高于边界温度的油膜温升;相同轴向位置处,周向温度几乎不变。

The temperature field of lubricating oil film of a piston skirt was studied theoretically by the eight-node iso-parametric finite elements method. Firstly, the Reynolds mixed-lubrication equation, the secondary moving equation of the piston skirt and the energy equation of oil film were given, and then these allied equations were solved by eight-node iso-parametric finite elements method based on the finite element solving steps and solving formulations. The calculation on engine shows that temperature field varies over a complete engine cycle. When the piston reaches the top dead center, the temperature of oil film decreases from the top part of piston skirt to the bottom part of piston skirt. When the piston is in the center of stroke, the phenomenon of oil film temperature over than the boundary temperature is observed. Meanwhile, the temperature of oil film varies little circumferentially for the specific axial position.