矩形腔内冷水稳态自然对流换热的二维数值模拟

为了了解矩形腔内非Boussinesq流体自然对流换热的特有现象和规律，利用有限容积法对矩形腔内的冷水自然对流进行了一系列数值模拟，得到了不同宽深比、Rayleigh数下的流场和温度场，并对不同条件下的壁面传热特性进行了比较与分析。计算结果表明：随着宽深比的增大，流动逐渐增强，流胞数逐渐增多，壁面平均Nusselt数逐渐增大，并趋于某一定值；随着Rayleigh数的增加，换热能力也会增强，而且流动结构的转变会在更小的宽深比下发生。采用逐步线性回归方法，得到了关于热壁平均Nusselt数的传热关联式。

Two Dimensional Numerical Simulation for Natural Steady Convection of Cold Water in Rectangular Cavity

In order to investigate the special phenomena and laws of natural convection for the non Boussinesq fluid in rectangular cavities, a series of steady two dimensional numerical simulations on natural convection of cold water in a rectangular cavity were conducted by using finite volume method. The flow and temperature fields for different aspect ratios of the cavity and Rayleigh numbers were obtained. The mean Nusselt numbers for different conditions were also compared and analyzed. The results show that the flow is enhanced and the number of cells increases with the increase of the aspect ratio of the cavity. The mean Nusselt number increases accordingly and finally approaches a constant value. With the increasing of the Rayleigh number, the heat transfer is enhanced and the transition of the flow structure will occur under smaller aspect ratio. Based on the simulation results, the heat transfer correlation were proposed according to the multiple linear regression.