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对具有导热和表面辐射换热相互耦合的封闭腔内的自然对流进行了数值研究,计算采用层流模型,为SIMPLE算法,QUICK差分格式.计算结果表明,在自然对流的封闭腔内,辐射换热比对流换热更占主导地位.当具有固体层时,导热的效应使总的对流换热有所增长(曲线的初始部分),但当固体层的导热系数比超过一定值时(kr≥10),再增加固体的导热性能,对封闭腔内的流动和换热的影响就不明显了.从数值上证实了在实际的建筑环境中,只要外围护结构的厚度达到一定的数值就可以达到隔热保温的要求.再增加厚度并不会得到更好的效果.
The numerical simulation of natural convection in closed cavity with heat transfer and surface radiation heat transfer is carried out. The laminar flow model is adopted to calculate the SIMPLE and QUICK difference schemes. The results show that in the natural convection closed cavity, Heat has a more dominant effect than convective heat transfer. With a solid layer, the effect of thermal conductivity increases the overall convective heat transfer (initial part of the curve), but when the thermal conductivity ratio of the solid layer exceeds a certain value (kr ≧ 10), and then increase the thermal conductivity of the solid, the closed cavity of the flow and heat transfer is not obvious.From the numerical verification in the actual construction environment, as long as the thickness of the outer envelope reaches a certain value Can achieve the requirements of thermal insulation. And then increase the thickness and will not get better results.