放热流体在多孔渗流水平圆柱外的自然对流

针对等温加热的多孔渗流水平圆柱体浸没在放热流体中的层流自然对流传热问题采用摄动法进行分析.圆柱体的多孔渗流特性用圆柱壁面的法向速度进行表示.通过摄动法对自然对流传热的边界层方程进行近似分析,并利用龙格-库塔方法求得方程的数值解,得到自然对流的速度与温度场以及沿圆柱体壁面的努塞尔数分布.结果表明,在有壁面外法向速度时,圆柱体的局部换热受到抑制；然而壁面吸入或流体放热效应都对局部努塞尔数有增强效果.圆柱体的平均努塞尔数随着流体放热的增加或壁面内法向速度的减小而降低.在流体放热恒定时,壁面流出效应对整体换热的影响并不明显.

Natural convection of a heat-generating fluid around a horizontal porous percolating circular cylinder

The perturbation method was employed to analyze laminar natural convection around an isothermally heated horizontal porous percolating circular cylinder that is immersed in a fluid with internal heat generation. The porous percolating effect of the circular cylinder was represented by its wall blowing/suction. The natural convection heat transfer boundary layer equations were solved using the perturbation technique incorporated with the Runge-Kutta method. The natural convective velocity and temperature profiles as well as the scaled local and overall Nusselt numbers were obtained. It was shown that the local Nusselt number is suppressed by wall blowing but is increased by either wall suction or heat generation,whereas the average Nusselt number is lowered with both increasing heat generation and decreasing wall suction. At constant heat generation,however,wall blowing has insignificant influence on the overall heat transfer.