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采用数值方法分析了填充多孔介质的竖直同心套管内,非均匀分布的内热源和内外壁面温差对自然对流的影响。考察了高宽比A、内热源分布系数m以及内外Rayleigh数之比Rai/Ra对流场、温度场和内外壁面Nusselt数的影响。结果表明：Rai/Ra较大时流场中部形成逆向环流,并出现θ＞1的高温区；内壁面Nusselt数呈现先增大后减小的趋势,大约在Z=0．8处出现转折。外壁面Nusselt数在Z＞0．8处变化加剧,表明外壁面对流传热主要集中在管上部区域。m增大流体中心逆向环流随之减小并最终消失。
The influence of the internal heat source with uneven distribution and the temperature difference between the inner and outer walls on the natural convection in the vertical concentric casing filled with porous media is analyzed numerically. The influences of aspect ratio A, internal heat source distribution coefficient m and ratio of internal and external Rayleigh numbers Rai / Ra on the flow field, the temperature field and the Nusselt number of the inner and outer walls were investigated. The results show that when the Rai / Ra is large, a reverse circulation occurs in the middle of the flow field and a high temperature region of θ> 1 appears. The Nusselt number of the inner wall first increases and then decreases, turning around at Z = 0.8. The Nusselt number of the outer wall changes more rapidly at Z> 0.8, indicating that the convective heat transfer on the outer wall mainly concentrates in the upper area of the pipe. m increases the center of the fluid reverse circulation decreases and eventually disappears.