内燃机冷却水腔表面形貌对沸腾换热影响的研究  

Study on Effect of Surface Morphology on Boiling Heat Transfer in Water Jacket of Internal Combustion Engine

作　　者：邱学军 白曙 侯刘闻迪 QIU Xuejun;BAI Shu;HOULIU Wendi(Kolbenschmidt Huayu Piston Co.,Ltd.,Shanghai 201814,China;Shanghai Diesel Engine Co.,Ltd.,Shanghai 200438,China;United Automotive Electronic Systems Co.,Ltd.,Shanghai 201206,China;School of Automotive and Traffic Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]华域科尔本施密特活塞有限公司,上海201814 [2]上海柴油机股份有限公司,上海200438 [3]联合汽车电子有限公司,上海201206 [4]江苏大学汽车与交通工程学院,镇江212013

出　　处：《柴油机设计与制造》2020年第1期9-15,共7页Design and Manufacture of Diesel Engine

摘　　要：愈发严重的能源和环境问题要求内燃机的结构更加紧凑和复杂,导致缸盖等零部件所受的热负荷急剧增加,这对其内部冷却水腔提出了更高的换热要求。对流换热已不能满足苛刻的冷却要求,沸腾换热应运而生。据气泡动力学可知,汽化核心更倾向于分布在狭窄的凹坑处,因此在加热面上布置一定的表面形貌能够有效提高沸腾换热效果。文中设计4种形貌,并比较分析不同形貌的强化换热能力。结果表明:圆柱形凸起形貌强化沸腾换热和对流换热的效果最好,其次是圆柱形凹坑形貌,圆台形凹坑强化沸腾换热的效果好于半球形凹坑形貌,但强化对流换热的效果比半球形凹坑形貌差。不同凹坑形貌,汽化核心更倾向于分布在凹坑底部的狭窄区域,圆柱形凹坑底部狭窄区域的范围最广,有利于汽泡成核,圆台形凹坑次之,而半球形凹坑内部较为平整,不利于成核。Recently,the internal combustion(IC)engine requires more compact structure due to increasingly serious energy and environmental problems.The cylinder head of engine stands so high thermal load that its inner water jacket requires good heat transfer capacity.The convective heat transfer can no longer satisfy the strict cooling requirements and the boiling heat transfer is therefore incorporated.According to the bubble dynamics,vaporization core is more inclined to distribute in a narrow area at the bottom of a cavity.Having a certain morphology on heating surface can effectively improve the boiling heat transfer.In this paper,four morphologies were designed to compare and analyze the ability of different morphologies in enhancing heat transfer.The results showed that a cylindrical bulge best enhanced the boiling heat transfer and convection heat transfer,followed by a cylindrical cavity.A round truncated-cone cavity enhanced the boiling heat transfer better than a hemispherical cavity,but the effect of strengthening the convective heat transfer was worse than that of the hemispherical cavity.The low flow area around the topography was wider,enhancing vaporization core,and average void fraction was more than that of the cavity.The top flow at the topography,however,was greater and suppressed the vaporization core,so the average void fraction was less.For different cavity topographies,the vaporization core was more inclined to distribute in the narrow area at the bottom of any cavity.The narrow area at the bottom of the cylindrical cavity was the widest,which was beneficial to bubble nucleation,and the truncated-cone cavity was the second.However,the inside of the hemispherical cavity was relatively flat,which was not conducive to nucleation.

关 键 词：冷却流道 沸腾换热 表面形貌 空泡份额 

分 类 号：U464[机械工程—车辆工程]