竖直环管内自然对流现象的试验和数值研究

Experimental and Numerical Investigations of Natural Convection in a Vertical Annulus

对一端开口另一端封闭的小间隙、长高度竖直环管内水的自然对流现象进行试验研究,并分别用严格域模型和延伸域模型进行数值计算。内管外壁面和顶部壁面保持绝热,外管外壁面进行通风冷却。冷却风速分别为2.9、5.7、8.6m/s,对应的格拉晓夫数(Gr)分别为9.8×106、3.9×106、8.3×105。结果表明:Gr<106时,2种模型的数值计算结果与试验结果偏差较小,且严格域模型得到的结果更接近试验结果;Gr>106时,2种模型的数值计算结果与试验结果偏差较大。

Experimental investigation of natural convection in a long vertical annulus closed at the top and opened at the bottom is presented. Numerical simulation is performed using the restricted domain model and extended domain model. The outer wall and top wall of inner cylinder are insulated. The outer wall of outer cylinder is cooled with the following speeds： 2.9, 5.7, 8.6rn/s. And the corresponding Grashof number is 9.8×106, 3.9×106, and 8.3×105. The discreP6ancy between the numerical and experimental results is small when Grashofnumber is less than 10 and becomes bigger when Grashofnumber exceeds 106.