小型强化内燃机燃烧室爆震流场及波致疲劳模拟  

Combustor detonation flowfield and wave-induced fatigue simulation of downsized engines

作　　者：王志坚 张佳明[3,4] 吕文芝 黄国龙 孟庆斌 WANG Zhijian;ZHANG Jiaming;LYU Wenzhi;HUANG Guolong;MENG Qingbin(State Key Laboratory of Engine Reliability,Weifang 261061,China;Weichai Power Co.,Ltd,Weifang 261061,China;School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Fluid and Interaction with Material,Ministry of Education,Beijing 100083,China)

机构地区：[1]内燃机可靠性国家重点实验室,山东潍坊261061 [2]潍柴动力股份有限公司,山东潍坊261061 [3]北京科技大学机械工程学院,北京100083 [4]教育部流体与材料相互作用重点实验室,北京100083

出　　处：《哈尔滨工程大学学报》2022年第8期1147-1155,共9页Journal of Harbin Engineering University

基　　金：内燃机可靠性国家重点实验室项目(SKLER-201907).

摘　　要：为了研究小型强化内燃机燃烧室在爆震工况下的可靠性,本文以小型强化内燃机热力学系统简化模型为基础,建立了燃烧室内热力学参数之间的数值关系。基于Rover K16内燃机模型,采用有限元模拟燃烧室爆震现象,对活塞进行热-机耦合仿真,预测活塞进行爆震工况下的寿命。通过改变缸内空燃比,得到了不同工况下的缸压曲线,验证了爆震激励实验。研究结果表明:爆震的发生没有使应力超过活塞的强度极限,但大幅度增加了活塞的应力及变形值,而且改变了活塞的危险点位置。活塞顶面外缘压力最大,达到210 MPa,远超过燃烧室中心高压区域的初始赋值。最先发生破坏的位置在活塞顶面中心、活塞内腔交界处及第1气环处,计算得到内燃机可连续运行249398 km,达到规定里程22万km。本文方法能够有效模拟爆震冲击波对活塞寿命产生的影响,对小型强化内燃机爆震工况下的寿命预测起到指导作用。To study the reliability of the combustion chamber of the downsized gasoline engine under knocking conditions,the numerical relationship between the thermodynamic parameters of the combustion chamber is established based on the simplified thermodynamic system model of a small intensified internal combustion engine.The knocking phenomenon of combustion chambers is simulated by the finite element method based on the Rover K16 gasoline engine model.By changing the air-fuel ratio in the cylinder,the cylinder pressure curves under different operating conditions are obtained,and the knock excitation experiment is verified.The thermal-mechanical coupling simulation of the piston is conducted to predict the life of the piston under the detonation condition.Results show that the occurrence of knocking maintained the stress exceed within the strength limit of the piston but has markedly increased the stress and deformation value of the piston and changed the dangerous point position of the piston.The pressure on the outer edge of the top surface of the piston is the largest,reaching 210 MPa,which is far beyond the initial assignment of the high-pressure area in the center of the combustion chamber.The first damage occurs at the center of the top surface of the piston,the junction of the inner cavity of the piston,and the first gas ring.Calculations reveal that the internal combustion engine can run continuously for 249398 km,reaching the specified mileage of 220000 km.The impact of detonation shock waves on piston life is effectively simulated,which plays a guiding role in the life prediction of downsized engines under detonation conditions.

关 键 词：小型强化内燃机 燃烧室 爆震波 强度 波致疲劳 热机耦合 疲劳寿命 活塞 应力 

分 类 号：TK412[动力工程及工程热物理—动力机械及工程]