矩形纵槽管的冷凝传热研究

A Study of Condensation Heat Transfer in Vertical Corrugated Tube of Rectangular Configuration

根据矩形纵槽管表面冷凝液流动的特点,将管长划分为流动过渡段与流动发展段。对前者按Nusselt理论。后者按表面张力强化(Gregorig)理论作了传热计算。结果表明:过渡段与发展段比较长度很小,在管长设计与传热计算中可忽略不计,波谷区液膜厚度沿管长分布以指数规律描述,由此算得的最大有效管长用于传热计算,所得结果与实验值有较好吻合。

Based on the characteristics of the condensing fluid flow on the surface of vertical corrugated tube,the length of the tube is divided into the transcient part and the developing part. Nusselt's theory and the theory of intensifying heat transfer by surface tension were applied to the two parts respectively, and the condensation heat transfer is calculated. The results indicate:1. The transcient length is very small as compared to the developing length. In designing the tube length and calculating the heat transfer ,the transcient length can be negleeted.2. The distribution of the condensed film thickness in the region of wave valley along the tube length can be described exponentially,and by which the maximum effective tube length can be obtained. The calculated capacity of heat transfer from these results conforms well with experimental datum.