管内插入网状肋强化换热的数值研究

Numerical Study of Heat Transfer Enhancement by Inserting Reticulated Ribs in Pipes

采用三维数值模拟方法研究了网状肋用于圆形通道的流动换热特征,分析了雷诺数Re、肋的形状、肋的网格间距、肋的直径以及流体与固体的导热系数比kf/ks对通道平均阻力系数和换热性能的影响,并引入换热性能评价指标PEC对2种网状肋进行了比较.结果表明:管内插入网状肋对流动阻力系数和换热性能有很大影响;方形肋的换热效果比圆形肋好,但其阻力较大;随着Re的减小,2种肋的降温效果均增强;肋的网格间距越小,则换热效果越好但阻力越大;随着肋直径的增大和流体与固体导热系数比kf/ks的减小,换热效果增强.

Flow and heat transfer characteristics of circular channels with reticulated ribs were studied by three-dimensional numerical simulation.The effects of Reynolds number（Re）,rib shape,rib grid spacing,rib diameter as well as the thermal conductivity ratio of fluid to solid（k_f/k_s） on average resistance coefficient and heat transfer performance of the channel were analyzed.Furthermore, a performance evaluation index PEC for heat transfer is introduced for the comparison of the two kinds of the reticulated ribs.Results show that the reticulated ribs which are inserted in the pipes have great effects on flow resistance coefficient and heat transfer performance.The rectangular rib has better heat transfer effect and bigger resistance than that of the circular rib. With the decrease of Re,the temperature reduction effect of the two ribs increase.The smaller the grid spacing of the rib is,the better the heat transfer is and the bigger the resistance is.With the increase of rib diameter and the decrease of the thermal conductivity ratio of fluid to solid（k_f/k_s）,the heat transfer is enhanced.