多孔介质流动显示与强化传热的实验研究

A experimental study on flow visualization and heat transfer augmentation of tube bundle

对添加挡流板、螺旋板及多孔介质的管束外掠流动的流型、流阻及其传热特性进行了实验研究。实验表明 ,直挡流板的管束流道由于存在滞留区 ,流阻高且不利于换热。螺旋板的管束流道的Nu比直挡流板高 79% ,而具有螺旋板和多孔介质组合的管束流道的对流换热系数比直挡流板高 94%。

The flow patterns, pressure drop, and heat transfer characteristics of tube bundles with different structure were studied. Experiments show that the heat transfer coefficient in tube bundles with segmental baffles is rather low, because of the stagnation region where the baffle attached the shell wall; and the pressure drop is high because of the zigzag flow. Since the helical baffled tube bundles eliminate both dead space and zigzag flow, the Nusselt number (Nu) is 94% higher than segmental baffled tube bundles. Meanwhile, the tube bundles with combination of helical baffles and porous media, the Nu is 79% higher than segmental baffled tube bundles.