摘要
采用数值模拟方法,在轴向通流雷诺数Rex为6400、旋转雷诺数Reω变化范围为0~3.77×10^(4)的条件下,对带轴向通流旋转管内部肋结构的流动传热特性进行了研究,着重研究了3种肋型结构,包括沿轴向布置的环形横肋、离散环肋和沿周向布置的纵向直肋。研究结果表明,旋转通道内流场受到轴向通流流动和旋转诱导周向流动的共同影响,在低旋转雷诺数下,轴向通流流动占主导,环肋和离散环肋的传热强化机制显著;而在高的旋转雷诺数下纵向肋的传热强化机制则更为显著。采用综合性能因子对几种肋型进行综合评价,在低旋转雷诺数下离散环肋的综合性能最优,但在高旋转雷诺数下,环肋和离散环肋结构的综合性能相较于光滑通道并无优势,甚至还会导致综合性能的降低。对于高速旋转管,纵向肋是内部强化传热应用的一种合理结构形式。
A numerical study was performed on the flow and heat transfer characteristics inside a rotating ribroughened pipe with an axial throughflow,under a fixed axial throughflow Reynolds number Rex 6400 and a series of rotational Reynolds number Reωranging from 0 to 3.77×10^(4).Three rib configurations were taken into consideration,including ring rib,discrete-ring rib and longitudinal rib,wherein the ring-type ribs were distributed along the axial direction and the longitudinal-type ribs were distributed along the circumferential direction.The results show that the flow field inside a rotating pipe is affected by both axial through flow and rotation-induced azimuthal flow.Under small rotational Reynolds numbers,the axial through flow is dominant such that the ring-type rib plays significant heat transfer enhancement role.Whereas under high rotational Reynolds numbers,the rotation-induced azimuthal flow is dominant such that the longitudinal-type rib is superior to the ring-type rib on heat transfer enhancement.In the view of a comprehensive performance factor that considers both heat transfer enhancement and flow loss together,the discrete-ring rib is identified to be the best among the current three rib configurations under small rotational Reynolds numbers.However,under high rotational Reynolds numbers,the ring-type ribs show no advantage over smooth pipe,and even lead to a reduction in comprehensive performance when compared to the smooth pipe.For the highspeed rotating pipe,the longitudinal-type rib is a promising rib configuration as applied to the heat transfer enhancement.
作者
王宇婕
孙文静
高齐宏
张靖周
WANG Yujie;SUN Wenjing;GAO Qihong;ZHANG Jingzhou(College of Energy and Power,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China)
关键词
旋转管
肋结构
轴向通流
流动传热
综合性能因子
rotating pipe
rib configuration
axial throughflow
flow and heat transfer
comprehensive performance factor
