螺旋缠绕波节管传热与流动性能分析

Heat transfer and flow characteristics analyses of helical tube with corrugation

以水为工质,对螺旋缠绕波节管湍流状态下传热与流阻性能进行数值计算,分析了其强化换热的机理,并分析了波节深度H与波节间距P对其传热与流动阻力的影响。结果表明:相同工况下,螺旋缠绕波节管的综合换热性能优于螺旋缠绕光管;流体在管内做螺旋运动,由于离心力的作用,在垂直流体主流方向上产生二次流;管横截面周期性的扩张与收缩,使流体在波节内产生沿流体主流方向上的回流,它们对流体边界层产生很强的破坏作用,使湍流程度增强,对换热有较好的强化作用;随着波节深度H的增大,Nu提高,f增大,综合传热性能逐渐提高;随着波节间距P的减小,Nu提高,f降低,综合传热性能逐渐提高。

Using water as the working fluid,the turbulent heat transfer and flow characteristic of helical tube with corrugation were numerically investigated. The heat transfer enhancement mechanism was analyzed,and the effects of corrugation height H and corrugation pitch P on heat transfer and flow characteristics were discussed. The simulation results indicated that the overall heat transfer performance of helical tube with corrugation was better than that of smooth helical tube in the same working condition,and that the centrifugal force coursed by the helical movement of fluid led to secondary flow in the vertical flow direction. Meanwhile,the back flow in main flowing direction was resulted from the periodic expansion and contraction of tube cross section,which destroyed the flow boundary layer,enlarged the turbulence intensity and strengthened the heat transfer process greatly. With increasing H,Nu and f the overall heat transfer performance increased. With decreasing P,Nu increased,f decreased and the overall heat transfer performance were improved greatly.