【摘要】 本文导出了垂直等热流壁前置以薄层高空隙率多孔介质条件下自然对流与辐射传热的控制方程,分别用数值和摄动方法求得了积分方程的数值解和零级、一级近似解.本文实验选用一层到三层不锈钢网作为多孔材料.实验表明,金属网显著地抑制了传热,网的层数、目数和间距对抑制传热的经济效果十分关键.理论所得的结果与实验吻合较好.更多还原

【Abstract】 Local-volume-average method has been used to derive the governing equations for the free convection and radiation heat transfer from a vertical flat plate of uniform wall heat flux with a thin layer of high porosity medium in front. Numerical solutions and analytical solutions to the zero and first order approximation have been found for the integral form of the governing equations. In the experiment, one to three layers of stainless mesh screens with different distanee between than wers used as high porosity material. The experimental results have shown the strong depreesion on both relation and free convection heat transfer iby installing mesh serjeens in front of the wall. The theoretical solutions meet with the experimental respite in reasonable degree. The in-flence of the thickness, permeability, optical length arid directionality of radiation of the porous medium as well as the distance between screens on the heat transfer have been discussed in the paper.更多还原