基于多场耦合的大缸径气缸盖的热机疲劳寿命预测仿真研究  

Thermal coupling fatigue life prediction of large diameter cylinderheads based on a multi-field coupling method

作　　者：张浩 刘勇[1] 李国超[1] 周宏根[1] 江景明 陆程翔 ZHANG Hao;LIU Yong;LI Guochao;ZHOU Honggen;JIANG Jingming;LU Chengxiang(School of Mechanical Engineering,Jiangsu University of Science and Technology,Zhenjiang 212100,China;Anqing Cssc Diesel Engine Co.Ltd.,Anqing 246000,China)

机构地区：[1]江苏科技大学机械工程学院,镇江212100 [2]安庆中船动力配套有限公司,安庆246000

出　　处：《江苏科技大学学报(自然科学版)》2025年第1期23-30,56,共9页Journal of Jiangsu University of Science and Technology:Natural Science Edition

基　　金：国家自然科学基金项目(52105450);高技术船舶科研项目(GBG5N21-2-2);江苏省高校基金项目(21KJB460016)。

摘　　要：缸内燃烧温度和冷却液流速的变化是影响气缸盖火力面疲劳裂纹、疲劳断裂等主要因素.采用多场耦合方法对SCE450型中速柴油机大缸径气缸盖的热机疲劳寿命进行了预测分析,并分析了缸内燃烧温度和冷却液流速对整体疲劳寿命的影响规律.采用缸内燃烧和水套冷却模拟分析方法为缸盖温度场的分析提供热分析边界条件,基于热-流-固耦合有限元方法计算了柴油机服役工况下气缸盖温度和应力应变变化趋势,并考虑温度对材料性能的影响,对气缸盖热机疲劳损伤和寿命进行了预测.研究结果表明:排气口附近出现最大的热应力为463.49 MPa,气缸盖火力面同侧的螺孔口附近的等效机械应力值最大,达到了269.15 MPa.疲劳寿命较低的区域主要分布在火力面的鼻梁区与启动阀处,最低寿命为24040次,缸内燃烧温度对整个气缸盖的疲劳寿命影响较大,但盲目提高冷却液的流速并不能提高气缸盖的疲劳寿命,因较大冷却液流速可能增大某些区域的温度差进而减少使用寿命,经过分析气缸盖560℃时,冷却液流速在3.0~5.0 m/s之间的疲劳寿命,得到冷却液流速在3.6 m/s时的疲劳寿命相对较长.Variations in combustion temperature and coolant flow rate significantly affect fatigue crack initiation and fatigue fracture of cylinder heads.A predictive analysis of the thermal-mechanical fatigue life of the SCE450-type medium-speed diesel engine′s large diameter cylinder head is presented using a multi-field coupling method in this study.The influence of combustion temperature and coolant flow rate on the overall fatigue life is analyzed.A simulation analysis method for combustion chamber and water jacket cooling is employed to provide thermal analysis boundary conditions for cylinder head temperature field analysis.Based on the thermal-flow-solid coupling finite element method,temperature and stress-strain variations of the cylinder head under service conditions are calculated.Considering the effect of temperature on material properties,thermal-mechanical fatigue damage and life prediction of the cylinder head are conducted in the end.The research findings reveal that the highest thermal stress occurs near the exhaust port,reaching 463.49 MPa,and the maximum equivalent mechanical stress near the threaded hole on the same side of the cylinder head fire surface reaches 269.15 MPa.Regions with lower fatigue life are mainly distributed in the nose beam area and starting valve of the fire surface,with the lowest life being only 24040 cycles.The combustion temperature significantly influences the fatigue life of the entire cylinder head.However,blindly increasing the coolant flow rate does not improve the fatigue life of the cylinder head.Higher coolant flow rates may increase temperature differences in certain areas,thereby reducing the overall service life.After analyzing the fatigue life of the coolant flow rate between 3.0 and 5.0 m/s at 560℃in the cylinder head,it is obtained that the fatigue life of the coolant flow rate at 3.6 m/s is relatively long.

关 键 词：大缸径气缸盖 热机耦合 有限元 疲劳寿命 

分 类 号：U664.1[交通运输工程—船舶及航道工程] TK422[交通运输工程—船舶与海洋工程]