不同高宽比的矩形空腔内流体浮升流动特性分析  

Flow characteristics of free fluid driven by buoyancy in rectangular cavities with different aspect ratios

作　　者：赵忠超[1] 张娇娇[1] 成华[1] 丰威仙[1] 

机构地区：[1]江苏科技大学能源与动力工程学院,江苏镇江212003

出　　处：《江苏科技大学学报（自然科学版）》2014年第6期557-562,共6页Journal of Jiangsu University of Science and Technology:Natural Science Edition

基　　金：江苏省产学研联合创新基金资助项目(BY2013066-09);国家自然科学基金资助项目(51205177)

摘　　要：应用无量纲分析方法,建立了矩形空腔内流体浮升流动的数学模型,研究了相同工况下不同高宽比对其流动换热的影响.研究结果表明:不同高宽比对流体的浮升流动具有较大影响,随着高宽比的增大,空腔内流体流动的层流过渡层向Ra值减小的方向偏移,且当Ra数一定时,Numean随高宽比迅速地达到最大值后缓慢减小;随着Ra值的增加,空腔中涡的数量逐渐增加,浮升流动强度增大,Numean增大,且Numean的最大值向高宽比减小的方向偏移.In this paper,the mathematic model of buoyant lift flow in a rectangular cavity was developed by the dimensionless analysis. The effects of aspect ratio of the rectangular cavity on the heat convection were simulated and analyzed through this mathematic model under same working conditions. The results show that the aspect ratio of rectangular cavity has great effects on the character of buoyant lift flow and heat convection efficiency. With the aspect ratio increased,the transition layer of laminar flow has the tendency to decrease the Rayleigh number.When the Rayleigh number is kept constant,the average Nusselt number dramatically approaches the maximum and then decreases gradually. The eddy amount,intensity of buoyant flow and the average Nusselt number increase with the Rayleigh number. The maximum of average Nusselt number also has the tendency to move in the direction of smaller aspect ratio.

关 键 词：矩形空腔 浮升流动 数值模拟 流体 

分 类 号：TK124[动力工程及工程热物理—工程热物理]