旋转方形截面螺旋管内流动与传热特性

利用数值计算方法研究了旋转矩形截面螺旋管内的粘性流动，分析了在离心力，科氏力共同作用下曲线管道中的二次流动结构、轴向流速分布、截面温度分布、摩擦系数比以及管道Nusselt数比随各参数的变化情况。计算结果表明：当旋转方向和主流方向相同时，旋转的作用与增大Dean数的作用相同，使得管道摩擦系数变大，管道换热效果增强，而当旋转方向和主流方向相反时，管道内流动结构变化十分明显，当F≈-1．2时(F为科氏力与离心力之比)，二次流出现类似于直扭管内的鞍状流动结构，轴向速度类似于静止直管内的流动结构，管道内的摩擦系数与静止直管内的摩擦系数大约相等，换热效果减至最弱；挠率对流动结构以及摩擦系数比和Nusselt系数比的影响效果与F有关。

Research on the Characteristics of Fluid Flow and Heat Transfer in a Rotating Helical Rectangle Duct

An incompressible viscous steady flow through a rotating helical rectangular duct is studied numerically . The combined effects of the rotation, the curvature and the torsion on the flow structure, the fraction factor ratio and the Nusselt number ratio are examined in detail for different aspect ratios. The results reveal that when the rotation has the same direction with the axial velocity, the effects of rotation are similar to increasing Dean number. But when the rotation has the opposite direction with the axial velocity, there exists evident difference. At (is the ratio of the Coriolis force to the centrifugal force), the friction factor and the Nusselt number reach their minimums and the flow behaviors are similar to that in a stationary twist ducts. The effect of torsion on flow behavior is dependent on F.