扁管传热与阻力特性的实验研究

Experimental Study on Characteristics of Heat Transfer and Flow Resistance in Flat Tube

以水为工质,对3种不同几何尺寸的扁管进行了传热与流阻的实验研究。相同换热条件下3根扁管的传热系数和管内传热系数均高于圆管,管内传热系数最大可提高到圆管的2.43倍。说明扁管具有很好的强化传热效果,但压降也高于圆管。同时对扁管在套管内水平和竖直2种放置方式的换热情况进行了对比,实验结果表明竖直放置的传热效果优于水平放置。

Taking water as a medium, the experimental study on the heat transfer and flow resistance of three fiat tubes with different geometric sizes is carried out. Experimental results show that the fiat tube and circular tube with the same perimeter are with the same Reynolds number under the same water flow rate, however the heat transfer coefficient of the three fiat tubes is higher than that of the circular tube and the largest heat transfer coefficient of the former can be 2.43 times of the latter. It is concluded that the fiat tube is with a good heat transfer enhancement effect. Pressure drop of the latter is however higher than that of circular tube. Finally, the heat transfer performance of horizontally and vertically laid fiat tube in the casing pipe is studied and compared, and the experimental result indicates that the vertical one gains the advantage over the other.