矩形通道中斜截半椭圆柱面传热和流阻数值模拟

Numerical Simulations on Heat Transfer and Flow Resistance of Oblique-cut Semi-elliptic Cylinder Shell in Rectangular Channel

在雷诺数Re=7000～26800范围内,对布置单排1对斜截半椭圆柱面的矩形通道内空气传热和流动特性进行三维数值模拟,用无量纲数R分析斜截半椭圆柱面斜截角α、攻角β、高度h、距入口间距S、前缘间距s、布置方式对其在通道内强化传热和流阻综合性能的影响。结果表明,在计算条件下,α=20o、β=15o、h=5 mm、S=100 mm、s=30 mm、渐扩式布置(前缘低后缘高、凹面相对)的斜截半椭圆柱面在通道内的强化传热和流阻综合性能最好。斜截半椭圆柱面在通道内产生的端部涡系对其强化通道内传热和流体流动结构的改变发挥了重要作用。

Three-dimensional numerical simulations were carried out to investigate heat transfer and fluid flow characteristics of a pair of single row oblique-cut semi-elliptic cylinder shells in a rectangular channel. The Reynolds number （Re） of air flow ranged from 7000 to 26800. The oblique angle a, angle of attack fl, height h, distance from the entrance S, spacing of two leading edges s and configuration of the oblique-cut semi-elliptic cylinder shells were considered. The dimensionless number R was used to analyze the effects of these six parameters on the comprehensive performance of heat transfer enhancement and flow resistance in the channel. The results showed that the oblique-cut semi-elliptic cylinder shells with a=-20°, β=15°, h=5 mm, S=100 mm, s=30 mm and configuration of common flow down （with lower leading edges and higher trailing edges, two concave surfaces facing each other） provide the best value of R under the considered conditions. The tip vortex system generated by oblique-cut semi-elliptic cylinder shells plays a vital role in heat transfer enhancement and change of flow structure in the channel.