摘要
针对汽车发动机舱内由于热量富集和结构拥挤而导致散热困难的问题,提出了双场耦合强化散热原理,并用于指导某款汽车的发动机舱内散热问题的分析与结构改进。首先,基于对流换热场协同理论,论述了发动机舱内高温部件强化散热的空气速度与温度梯度的0°夹角原则,并据此根据自然对流换热下的温度场分布特征,推导了入流空气速度的"辐射状"优化方向;然后,针对某款汽车发动机舱内排气歧管散热不足问题,基于"辐射状"优化方向进行舱内流场散热分析和结构改进研究,确定了"散热器-风扇"导流罩组合的结构改进方案。最终结果表明,排气歧管对流换热系数提高了37.5%,表面平均温度降低了24.4%,周围局部高温消除,解决了舱内散热不足问题。
Aiming at the heat dissipation difficulty of vehicle engine compartment caused by heat accumulation and structural congestion,a principle of velocity field-temperature field coupling intensified heat dissipation is proposed as a guide for the heat dissipation analysis and structural modification of a car engine compartment.Firstly,based on convective heat transfer field synergy theory,the principle of 0° angle between air velocity and temperature gradient for the intensified heat dissipation of hot components in engine compartment is expounded,and on this basis,the 'radial'optimized direction of inflow air velocity is derived according to the distribution characteristics of temperature field under natural convection heat transfer.Then,aiming at the poor cooling of exhaust manifold in a car engine compartment,a study on the flow field heat dissipation analysis and structural modification of engine compartment is conducted based on 'radial'optimized direction,with a scheme of 'radiator-fan'deflector combination modified structure determined.The final results show that the convective heat transfer coefficient of exhaust manifold is enhanced by 37.5%,its average surface temperature is lowered by 24.4%,and the hot spots around exhaust manifold is eliminated,so the inadequate heat dissipation issue of engine compartment is resolved
出处
《汽车工程》
EI
CSCD
北大核心
2017年第8期879-888,共10页
Automotive Engineering
基金
湖南省教育厅高等学校科学研究计划优秀青年项目(2015B066和2016B072)
湖南省自然科学基金(2017JJ2074)
中央财政汽车空气动力学及关键零部件设计与制造创新团队项目(0420036017)资助
关键词
发动机舱
散热
双场耦合
结构改进
engine compartment
heat dissipation
velocity field-temperature field coupling
structural modification
作者简介
通信作者：张勇,博士研究生,E-mail：zhangyong7051678@163.com.
