【摘要】 为了研究过渡流下在壁面附近插入不同直径圆柱对壁面强化传热的影响,采用基于复合网格系统的数值计算方法,在雷诺数Re=200时,对圆柱直径D为5～14 mm的近壁圆柱绕流进行了数值计算.利用低速循环水槽试验台进行可视化流动试验,以验证数值计算方法的可靠性.结果表明:近壁插入圆柱可以使流动提前进入利于传热的过渡流状态;当间隙比C/D(C为圆柱与下壁面之间的距离)相同时,改变D仅影响■曲线第2个波峰的大小和发生位置;D越大,圆柱尾流中周期性脱落的涡以及壁面旋涡的大小和强度越大,且发生位置逐渐向下游移动;过渡流范围内D越大,圆柱下游壁面强化传热越大、作用区域亦越大;不同D下,■曲线第2个波峰达到最大的最佳插入位置C基本保持不变,D越大,最佳间隙比C/D越小.更多还原

【Abstract】 To investigate the effect of inserting cylinder with different diameters near the wall on the heat transfer enhancement of wall in transition flow, a numerical calculation method was used based on a composite grid system. When Reynolds number of Re was 200 with cylinder diameter of D from 5 mm to 14 mm, the numerical calculations for the flow around cylinder near the wall were carried out. The low-water-velocity flume test rig was used to verify the numerical calculation method. The results show that the inserting cylinder near the wall can bring the flow into transition flow state in advance, which is beneficial to heat transfer. For the same gap ratio of C/D with C meaning the distance between the cylinder and the lower wall, changing D just affects the size and location of the second peak. With the increasing of D, the size and strength of the periodic shedding vortex and near-wall vortex in the wake of cylinder are increased, and the occurrence location gradually moves downstream. As D is increased within the transition flow range, the heat transfer enhancement on the downstream wall is increased with increased action area. Under different D, the optimal insertion position of C for the second peak of the curve reaching the maximum remains basically unchanged. With the increasing of D, the optimal gap ratio of C/D is decreased.更多还原