摘要
以非道路四气门增压中冷柴油机为研究对象,通过台架试验测试了不同工况下缸盖火力面温度场及冷却水套进出水口流量、温度等参数,建立了准确的整机有限元模型与冷却水套流动CFD模型,对冷却水套流场及缸盖热负荷进行仿真分析,优化了水套结构。仿真分析结果表明,缸盖的高温区域主要集中在各缸火力面区域,两排气门之间的鼻梁区热负荷较高,最高温度为337.5℃;由于流动不均匀,缸盖水套壁面的换热系数分布不均匀,差值为62 172 W/(m^2·K);缸盖预紧工况、热载荷工况、爆发工况下最大等效应力分别为242.72,301.25,300.43 MPa,最大应变分别为0.047,0.439,0.458mm,对缸盖强度与刚度影响最大的是所承受的热载荷;对缸盖水套结构进行优化,优化后换热系数均值由8 906 W/(m^2·K)升高到9 065 W/(m^2·K),且分布更加均匀,鼻梁区最高温度降低了9.12℃,各测点温度平均下降6~10℃;缸盖最大应力下降22.71 MPa,最大变形下降0.011 mm,优化效果显著。
In this article,with the non-road four-valve supercharged and intercooled diesel engine as the research focus,a series of bench tests are conducted to identify the temperature field of the cylinder head’s fire surface as well as such parameters as the flow and temperature of the cooling water jacket’s inlet and outlet under different working conditions. As a result,both the accurate finite-element model of the whole machine and the CFD flow model of the cooling water jacket are set up to simulate and analyze the cooling water jacket’s flow field and the cylinder head’s thermal load. Thus,the structure of the water jacket is optimized. The simulation results show that high temperature of the cylinder head is mainly concentrated on the fire surface of each cylinder,and the thermal load in the nose bridge area between the two exhaust valves is high,with the highest temperature of 337.5 ℃;due to the uneven flow,the heat-transfer coefficient is unevenly distributed,with a difference of 62 172 W/(m^2·K);the maximum equivalent stresses under the preload conditions,thermal load conditions,and burst conditions of the cylinder head are 242.72,301.25,300.43 MPa respectively;the maximum strain is 0.047,0.439,0.458 mm;thermal load exerts the greatest impact on the strength and stiffness of the cylinder head;the structure of the cylinder head’s water jacket is optimized;the average heat-transfer coefficient after optimization increases from 8 906 W/(m^2·K) to 9 065 W/(m^2·K),and its distribution is more uniform;the maximum temperature of the nose bridge area decreases by 9.12 ℃,and the temperature at each measurement point decreases by 6~10 ℃ on average;the cylinder head is significantly optimized,with its maximum stress decreasing by 22.71 MPa and its maximum deformation reducing by 0.011 mm.
作者
肖奔
毕玉华
逯飞飞
刘少华
黄粉莲
XIAO Ben;BI Yu-hua;LU Fei-fei;LIU Shao-hua;HUANG Fen-lian(Yunnan Key Laboratory of Internal Combustion Engine,Kunming University of Science and Technology,Kunming 650500)
出处
《机械设计》
CSCD
北大核心
2020年第4期28-36,共9页
Journal of Machine Design
基金
国家自然科学基金资助项目(51765025)
云南省基础研究重点资助项目(2018FA030)
云南省科技创新人才计划资助项目(2018HC021)。
关键词
非道路柴油机
四气门
缸盖
机械负荷
热负荷
non-road diesel engine
four valves
cylinder head
mechanical load
thermal load
作者简介
肖奔(1995-),男,硕士,主要研究方向:内燃机排放控制。E-mail:ydfq_2633@163.com;通信作者:毕玉华(1967-),女,教授,博士,主要研究方向:内燃机现代设计。E-mail:yuhuabi@sina.com。
