余隙率对内置扭带换热管传热性能影响的数值研究

为了研究管内插入扭带对换热的影响,建立了余隙率分别为0.1,0.15,0.2,0.25,0.3的内置扭带换热管流体流动的三维物理模型,采用RNGk-ε湍流模型对这几种余隙率的扭带换热管的流动和传热特性进行了数值模拟,分析了插入不同余隙率扭带换热管的换热效果和流动阻力。结果表明,Nu数和摩擦阻力系数均随着余隙率的增大而减小,在低Re数的时候内置扭带有明显的经济性,特别是余隙率为0.1的扭带换热管综合性能最高,强化传热效果最为明显。

Numerical study of clearance ratio impact on the convective heat transfer in tube with twisted-tape inserts

The three-dimensional physical model of fluid flow in tube with twisted-tape inserts was established to study the effects brought by twisted-tape on heat transfer,the clearance ratios of twisted-tape were 0.1,0.15,0.2,0.25 and 0.3 respectively.The Renormalized Group（RNG） k-ε turbulence model was used to simulate the effect of heat transfer and flow resistance of these heat transfer with twisted-tape which has different clearance ratio.The result showed that Nu number and friction factor decreased with the increase of the clearance ratio,the heat transfer with twist-tape inserts was obvious economic when Re number was low.In particular,the comprehensive performance of heat transfer tube with clearance ratio of 0.1 was the highest,and the enhancement of heat transfer was most obvious.