波纹管管外冷凝特性的研究

以煤油蒸汽和水蒸气为工质研究了波纹管管外冷凝时的传热特性。试验中采用内管为波纹单管的套管换热器,分为水平和垂直2种布置方式。在不同流速下,根据试验测量的温度和流量等参数计算波纹管管外传热系数;并与相同参数(流速、温度)条件下光管管外传热系数的理论计算值进行比较。结果表明:随液相雷诺数的提高,传热系数随之提高,相对光管,波纹管管外传热系数有明显提高;波纹管有效地增强了管外冷凝传热;水作为单一工质相对于多组分的煤油,波纹管对其管外冷凝强化效果更好。

Investigation on condensation heat transfer outside corrugated tube

An experimental investigation on the condensation heat transfer of water and kerosene outside corrugated tube was carried out.The sleeving heat exchanger whose inside tube is corrugated tube was used in the experiment.It was placed in both horizontal direction and vertical direction.At different velocities of flow,the condensation heat transfer coefficient of corrugated tube was calculated based on the experimental data.And it was compared with the theoretical calculation value(based on the same temperature and velocity of flow) of smooth tube.The results show that as the liquid-film Reynolds number increases,the condensation heat transfer coefficient increases;and the condensation heat transfer coefficient of corrugated tube is greater than that of smooth tube.The corrugated tube improves the condensation heat transfer outside tube.This improvement of corrugated tube for water is more obvious than that for kerosene.