椭圆扭曲螺旋管传热及流阻特性模拟研究

Numerical studies on flow and heat transfer in twisted ellipse helical coiled tubes

针对强化传热的椭圆扭曲螺旋管(TEHCT)结构,建立其物理模型。在雷诺数10000<Re<40000,数值模拟研究了椭圆扭曲螺旋管不同结构参数对其流动传热性能及压降的影响,发现离心力引起的二次流促进边界层的破坏,强化传热。数值计算结果表明:随着椭圆扭曲螺旋管的扭曲数T和长短轴比A/B增大,以及螺旋直径D和螺距H减小,管内传热系数及压降相应增加。其综合性能随着扭曲数T和长短轴比A/B的增大而降低,但仍优于螺旋圆管。通过计算结果的拟合获得了椭圆扭曲螺旋管传热及压降的计算准则关系式。

Structures of twisted ellipse helical coiled tubes(TEHCT)for heat transfer enhancement were proposed and the related models were established.Effects of different structural parameters of the TEHCT with Reynolds number in the range of 10000<Re<40000 on heat transfer and pressure drop were studied numerically.The results show that the secondary flow caused by centrifugal force promotes the destruction of the boundary layer and enhances heat transfer.The heat transfer coefficient and pressure drop in the TEHCT increase with the increase of the twist number T and the axial ratio A/B,while they increase with the decrease of the spiral diameter D and the pitch H.The comprehensive performance of the TEHCT decreases with the increase of twist number T and the axial ratio A/B,which is still better than helical coiled tubes.The correlations for calculating the heat transfer and pressure drop of TEHCT were fitted.