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本文模拟研究了变物性空气在多种正多边形和圆形通道内的湍流流动和换热特性。选用标准k-ε湍流模型以及SIMPLE算法对此三维椭圆型问题进行求解。模拟结果表明:对于正多边形截面通道,角区的换热要明显弱于非角区区域,且恶化程度随着角区角度的减小而加剧,同时,角区角度越小,管壁的周向换热系数分布越不均匀;正多边形通道与圆形通道平均换热Nu的差异随着正多边形边数的增多而减小;借助当量直径,使用针对圆形通道的湍流换热关联式计算非圆截面通道内的换热将会带来较大误差,对于正多边形通道,这种最大误差存在于正三角形通道与圆形通道之间,误差可达27.5%。
This paper simulates the turbulent flow and heat transfer characteristics of variable air in a variety of regular polygons and circular channels. The standard k-ε turbulence model and the SIMPLE algorithm are used to solve this three-dimensional elliptic problem. The simulation results show that the heat transfer in the corner zone is obviously weaker than that in the non-corner zone for the regular polygon cross-section channel, and the degree of deterioration aggravates with the decrease of the angle in the corner zone. At the same time, The more non-uniform the heat coefficient distribution; the difference of the average heat transfer Nu of the regular polygon channel and the circular channel decreases with the increase of the number of regular polygons; with the equivalent diameter, the non-circular The heat transfer in the cross-section channel will bring greater error. For the regular polygon channel, the maximum error exists between the equilateral triangle channel and the circular channel, with an error of up to 27.5%.