壁面辐射对具有内置翅片的封闭腔内湍流自然对流传热特性影响  

Effect of Wall Radiation on Turbulent Natural Convection Heat Transfer Characteristics in an Enclosed Cavity with Built-in Fins

作　　者：王烨[1,2] 赵兴杰 马兵善 管国祥[1] Wang Ye;Zhao Xingjie;Ma Bingshan;Guan Guoxiang(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou,730070,China;Key Laboratory of Railway Vehicle Thermal Engineering,Ministry of Education of China,Lanzhou Jiaotong University,Lanzhou,730070,China)

机构地区：[1]兰州交通大学环境与市政工程学院,兰州730070 [2]兰州交通大学铁道车辆热工教育部重点实验室,兰州730070

出　　处：《核动力工程》2020年第2期89-95,共7页Nuclear Power Engineering

基　　金：国家自然科学基金(51476073,51266004);甘肃省建设科技攻关项目(KJ2016-2)。

摘　　要：为研究有内置翅片的封闭腔内壁面发射率(ε)对腔内湍流自然对流传热特性的影响,采用RNG k-ε湍流模型对流体为空气、高宽比为1的封闭腔内的温度场、流场、壁面传热能力进行数值分析。结果表明:内置翅片与壁面辐射的综合效应使得竖向热边界层和速度边界层厚度均增大,腔体顶部及底部区域水平速度产生了一定波动。考虑壁面辐射时,双翅片结构对热壁面局部传热能力的影响趋势与单翅片结构类似;ε为0.3、0.6、0.9时,单翅片对热壁面平均努塞尔数(Nu)分别提高39.95%、88.55%和144.97%,双翅片对热壁面平均Nu分别提高41.09%、87.32%和141.23%;ε过大对双翅片结构的封闭腔内对流散热反而不利。In order to study the effects of wall emissivity on natural convection heat transfer characteristics of an air-filled enclosure with built-in fins,the RNG k-εmodel was adopted to numerically analyze the temperature field,the flow field and the Nusselt numbers on the vertical wall of the cavity with aspect ratio of 1.The results show that the thickness of the vertical thermal boundary layer and the vertical velocity boundary layer are both increasing due to the combined effect of the built-in fin and the wall radiation.And the horizontal velocity of the top and bottom regions of the cavity fluctuates to a certain extent.When considering wall radiation,the effect of double fins structure on the local heat transfer capacity of the hot wall is similar to that of the single fin structure.When the inside wall emissivity is set to 0.3,0.6 and 0.9,respectively,correspondingly,the average Nusselt number on the hot wall of single fin cavity will increase by 39.95%,88.55%and 144.97%compared with that under the condition of no radiation.Meanwhile,the average Nusselt number on the hot wall of double fins cavity are increased by 41.09%,87.32%and 141.23%compared with that of no radiation,respectively.For the enclosed cavity of the double-fin structure,high wall emissivity is disadvantageous to the convection heat transfer.

关 键 词：封闭腔 自然对流传热 辐射 耦合传热 数值分析 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TL33[动力工程及工程热物理—热能工程]