热壁面位置对矩形腔内自然对流影响的数值分析

对矩形腔内冷热壁面位于侧壁不同相对位置时的自然对流换热问题进行了数值模拟.腔体左侧局部壁面维持恒定高温,右侧局部壁面维持恒定低温,左右侧壁的其它部分以及顶部和底部壁面绝热.按照冷热壁面的相对位置是否左右对称,通过改变Rayleigh数的大小,分析了不同工况下矩形腔内温度场、流场和热壁表面平均Nusselt数的变化,得到了Rayleigh数在103~106之间的结果.冷热壁面对称分布时,位于侧壁中部的换热作用最强;不对称分布时,热壁面位于侧壁中部、冷壁面位于侧壁上部的换热作用最强.

Numerical Analysis on Natural Convection in Rectangular Cavity Influenced by Positions of Thermal Walls

A numerical simulation was performed to study the natural convection and heat transfer of fluid contained in a rectangular cavity influenced by the different positions of thermal walls.The partial part of the left side wall was set at a high constant temperature and the partial part of the right side wall was set at a low constant temperature.The other parts of the side walls and the top and bottom of the cavity were thermally insulated.Under the conditions of symmetrical or a symmetrical location of thermal walls,the flow and temperature fields and the average Nusselt number of thermal walls were analyzed under different Rayleigh numbers.The results were obtained with Rayleigh numbers between 10³ and 10⁶.The heat transfer rate is high at the middle part of thermal walls in symmetrical case and at the middle-top part in asymmetrical case.