强化缸盖鼻梁区传热的水腔表面结构设计研究

Surface Structure Design of Water Cavity for Enhancing Heat Transfer in Bridge Zone of Cylinder Head

针对高强化柴油机气缸盖排气门鼻梁区严重的热负荷问题,提出在该区域冷却水腔中建立特殊的结构表面以强化其传热的能力,并建立8种不同的特殊结构表面.采用欧拉多相流以及壁面沸腾换热模型分别对8个不同结构表面的鼻梁区简化流道进行流动传热仿真分析,并设计了流动沸腾试验平台,验证仿真计算的可靠性.在此基础上,研究各种结构表面对表面流动的扰乱程度以及对传热系数的影响,最后进行各结构表面传热能力的综合评价.结果表明:特殊的表面结构对表面湍流强度以及传热系数有不同程度的影响,其中柱体结构表面与两种槽肋结构表面对湍流强度的提升都达4.9倍以上,叉排式柱体结构表面与垂直流向的槽肋结构表面的提升传热系数分别提升了65.9%和57.4%;并且在传热能力的综合评价得到上述3种结构对火力面最高温度降低均达23℃以上.

In view of the serious heat load in the bridge zone of the cylinder head of a high reinforced diesel engine,8 different special structural surfaces were established to strengthen its heat transfer capacity in the cooling water jacket of the region.The simulation analysis of flow and heat transfer in the simplified channel of 8 different structural surfaces was carried out by using Euler multiphase flow and wall boiling heat transfer model.A flow boiling experimental platform was also designed to verify the reliability of the simulation.On this basis,the degree of disruption of the surface flow of various structures and the influence on the heat transfer coefficient were studied.Finally,a comprehensive evaluation of the heat transfer capacity of the various structures was performed.The results show that the special surface structure has different influence on the turbulence intensity and the surface heat transfer coefficient,in which the surface of the column structure and the surface of the two type groove ribs are 4.9 times higher than that of the turbulence intensity.The enhancement of heat transfer coefficient of the fork-row column structure and the surface of the vertical rib structure are increased by 65.9%and 57.4%,respectively.And in the comprehensive evaluation of heat transfer ability,the above three structures can reduce about 23℃of the maximum temperature of the fire surface.