摘要
针对进气过程中活塞顶面温度分布不均匀,会对活塞疲劳寿命计算产生影响的问题,采用燃烧模拟和有限元方法,结合材料试验,进行了活塞低周疲劳寿命预测。首先,通过CFD仿真,获取了考虑进气冷却效应的燃烧室温度分布,有限元仿真计算了活塞温度和应变;然后,进行了 573 K下的活塞材料拉伸试验和疲劳试验,获取了活塞材料力学参数并推导出活塞疲劳寿命预测模型;最后,结合活塞应变和疲劳寿命预测模型,对比分析了进气冷却效应对活塞低周疲劳寿命的影响。研究结果表明:考虑进气冷却的燃烧室,燃气温度分布不对称,进排气侧的温差达到了 75 K左右;活塞应变较大的位置主要集中在活塞凹坑底部、冷却油腔内部、环岸内部和活塞销孔上半部;考虑进气冷却效应导致活塞最大应变值上升了 0.425%,低周疲劳寿命降低了 13.8%。
Piston is a key component of diesel engine,and its fatigue life directly affects the normal operation of the engine.Aiming at the problem that the temperature distribution on the piston top surface may affect the fatigue life calculation during the intake process,combustion simulation and finite element method are combined with the material test to predict the piston’s low cycle fatigue life.The combustor temperature was obtained by CFD simulation,and the piston temperature and strain were calculated by finite element method.Through the tensile and fatigue tests of piston material at 573 K,the mechanical parameters of piston material were obtained,and the fatigue life prediction model was deduced.Finally,the effect of intake cooling on the low cycle fatigue life of the piston was analyzed by the piston strain and fatigue life prediction model.The results showed that the temperature of the combustion chamber is asymmetrical,and the temperature difference between the inlet and exhaust sides reaches about 75 K.The large strains occur at the bottom of piston pit,inside the cooling oil chamber and the bank,and at the upper half of the piston pin hole.Considering the intake air cooling effect,the maximum strain of the piston rises by 0.425% and the low cycle fatigue life decreases by 13.8%.
作者
李云强
赵立普
李伟东
王静超
徐天舒
张俊红
LI Yunqiang;ZHAO Lipu;LI Weidong;WANG Jingchao;XU Tianshu;ZHANG Junhong(State Key Laboratory of Engine Reliability,Weifang,Shandong 261061,China;Weichai Power Co.,Ltd.,Weifang,Shandong 261061,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China;Ren’ai College,Tianjin University,Tianjin 300072,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第7期45-51,共7页
Journal of Xi'an Jiaotong University
基金
内燃机可靠性国家重点实验室开放课题资助(skler-201713)
关键词
活塞
进气冷却
热-机耦合
疲劳寿命
piston
inlet air cooling
thermo-mechanical coupling
fatigue life
