烧结开孔金属泡沫壁的辐射和自然对流耦合换热试验研究  

Combined Heat Transfer of Radiation and Convection on Wall Sintered with Open Celled Metallic Foams

作　　者：汪天送[1] 屈治国[1] 陶文铨[1] 卢天健[2] 

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,西安710049 [2]西安交通大学强度与振动教育部重点实验室,西安710049

出　　处：《机械工程学报》2011年第4期131-135,共5页Journal of Mechanical Engineering

基　　金：国家自然科学基金(50806057);国家重点基础研究发展计划(973计划;2011CB610306);教育部新教师基金(200806981013);教育部新世纪人才计划(NCET-10-0640);全国优秀博士学位论文作者专项基金(201041)资助项目

摘　　要：开展烧结开孔金属泡沫壁在大空间条件下的辐射和自然对流耦合换热试验研究,研究壁面倾角、瑞利数Ra*、泡沫厚度对换热性能的影响。试验所得竖直光铜板的结果与文献结果符合一致,验证了试验方案的有效性。试验结果表明:在一定的加热功率下,随着倾角的增加,纯自然对流努塞尔数和复合努塞尔数先增加后减小,在倾角为60o～80o达到极大值,且辐射换热量占总换热量的33%～44%;竖直放置时,烧结泡沫壁的辐射换热量占总换热量的比值小于光壁,且该值随泡沫厚度增加而增加。与光壁相比,烧结泡沫竖壁复合换热的平均努塞尔数和纯自然对流换热的平均努塞尔数分别提高了1.52～1.98倍和1.16～1.66倍。通过对红外相机拍摄的泡沫表面温度分布进行分析验证了基于泡沫表面平均温度的辐射换热量计算模型的有效性。Experimental investigation of the combined radiation and natural convection heat transfer on wall surface sintered with open celled metal foams at different inclination angles is presented.The effects of wall inclination angle,Rayleigh number Ra＊ and thickness on heat transfer performance are studied.The heat transfer results for vertically placed smooth cooper plate are in good agreement with the available data in the literature to show the feasibility of the test rig.With increasing of the inclination angle under the same heat flux,the pure natural convection heat transfer coefficient and total heat transfer coefficient increase firstly to a turning point and then decrease.The maximum heat transfer performance occurs at an inclination angle between 60° and 80°.The radiation heat transfer accounts for 33%～44% of the total heat transfer.When placed vertically,the ratio of radiation heat transfer of metallic foam sintered surface in the total heat transfer is less than that of the smooth surface,and is improved with increasing of metal foam thickness.Compared to the smooth surface,the mean Nusselt numbers of combined heat transfer and pure natural convection heat transfer of vertically placed sintered surface increase by 1.52～1.98 and 1.16～1.66 times respectively.The temperature distribution on foam surface photographed by infrared camera are analyzed with image processing technique to validate the thermal radiation heat transfer calculation model based on average foam surface temperature.

关 键 词：辐射与自然对流耦合换热 开孔金属泡沫 倾角 瑞利数 厚度 

分 类 号：TK124[动力工程及工程热物理—工程热物理]