复合隔热组合活塞结构设计及优化

Structural Design and Optimization of the Composite Insulated Piston

提出一种采用空气和隔热衬垫复合隔热的钢顶铝裙活塞,其中活塞顶、隔热衬垫和铝裙通过4个对称螺栓连接.为了解该活塞结构特性,开展组合活塞热边界分析,并进行活塞温度场仿真与试验测试对比,揭示空气隔热腔及隔热衬垫对整体活塞温度场的影响.结果表明:经活塞环槽区输出的热流减小约为20%,后续进行组合活塞机械应力及接触面压对比分析,验证了仿真模型的有效性.在此基础上进一步开展活塞热机应力分析,针对隔热衬垫与活塞顶接触面应力状态较差的部位,通过组合活塞结构匹配优化降低了结构应力幅值、改善了应力分布,其中应力幅值降低约为50%,据此最终完成复合隔热组合活塞设计.

A composite insulated piston with air-gap and heat insulating gasket was presented,in which the piston crown,insulation gasket and aluminum skirt are connected by four symmetrical bolts.In order to investigate the characteristics of the mentioned piston,the thermal boundary of the piston was analyzed and the temperature field of the piston was simulated and tested.It is revealed that the air-gap and insulation gasket has important effect on the overall piston temperature field.The heat flow through the piston ring groove is reduced by about 20%.Then,a mechanical simulation model was verified by comparison analysis of the mechanical stress and the contact surface pressure.The thermal-mechanical stress was calculated and the worst stress area between the insulation gasket and the piston crown was obtained.Next,the structural optimization of the composite piston was carried out and the results show that the stress amplitude is reduced by about 50%and the stress distribution is improved.The design of the composite insulated piston was finally completed.