摘要
针对某重型车用六缸柴油机气缸盖热负荷过高、鼻梁区出现热裂情况,对冷却水套内的三维流动进行了数值模拟。根据数值模拟结果,提出了4种冷却水套改进方案,其中改进方案1使气缸盖底部的冷却水流速增大了68.73%,鼻梁区对流换热系数提高了56.55%。气缸盖底部温度测量结果表明,气缸盖鼻梁区最高温度降低9.2℃,垂直温度梯度降低19.55%,较好地改善了该型柴油机气缸盖的热负荷。
In view of the excessive thermal load in cylinder head and the occurrence of thermal crack in the valve-bridge region of a 6-cylinder diesel engine in a heavy-duty vehicle, a numerical simulation on 3-D flow of water jacket is carried out. According to the analysis on the results of numerical simulations, 4 modification schemes for water jacket are put forward, from which one scheme is chosen with comprehensive considerations of the coolant flow field in water jacket and the cost of modification. With the scheme, the mean flow rate of coolant at the bottom of cylinder head increases by 68.73% and the convection-heat-transfer-coefficient in valve-bridge region rises by 56. 55%, the maximum temperature in valve-bridge region lowers by 9. 2℃ and the temperature gradient reduces by 19. 55%. So the thermal load of cylinder head is improved.
出处
《汽车工程》
EI
CSCD
北大核心
2008年第4期312-316,共5页
Automotive Engineering
关键词
柴油机
气缸盖
流动与传热
数值模拟
diesel engine
cylinder head
flow and heat transfer
numerical simulation
