基于活塞温度场的发动机热负荷分析及控制

Analysis and Control of Engine Thermal Load Based on Piston Temperature Field

针对四冲程高速柴油机活塞热负荷问题,建立了基于两相流振荡换热的活塞热流固耦合模型,该模型考虑了活塞往复运动造成机油无法填满冷却内腔的问题,通过设定气相、液相的多相流方法,模拟出机油在冷却内腔中填充率的变化曲线,并对各转角的瞬态传热系数及温度求平均值,从而进行热流固耦合分析。通过与硬度塞测量法的试验结果进行对比,可知该模型的误差较小,可以较好地用于活塞温度场的仿真模拟及关键位置热负荷的评估分析。在此基础上进行活塞热负荷影响因素的规律性分析,得到满足热负荷要求的发动机运行区间。

Aiming at the thermal load problem of four-stroke highspeed diesel engine piston,a thermal fluid-solid coupling model of piston based on two-phase flow oscillating heat transfer was established by considering the problem that the cooling cavity cannot be full of lube oil fill due to the reciprocating motion of piston.The multiphase flow method that consisted of gas phase and fluid phase simulated the change curve of lube oil filling rate in the cooling cavity and averaged the transient heat transfer coefficient and temperature of each corner to perform thermal fluid-solid coupling analysis.Compared with the experimental results of hardness plug measurement method,it was verified that the model error was small and so it could be well used for the simulation of piston temperature field and the evaluation and analysis of thermal load at the critical position.The law analysis of the factors affecting the thermal load of piston was carried out and the engine operation range that met the thermal load requirement was acquired.