管内冷凝传热计算方法探讨

An Approach Method for the Calculation of Condensing Film Heat Transfer in Tube

常用的冷凝传热计算方法为Akers的经验公式和以Nusselt理论为基础演变出的关联式。前者以当量雷诺数划分两段计算，但在雷诺数过低或过高时偏差过大；后者以液膜雷诺数分三段计算，其结果更可信，但计算结果是瞬时值，不能代表平均值。文章对不同计算方法进行比较，并针对存在的问题提出了改进意见。

The ordinary method for the calculation of condensing film heat transfer in tube is Akers or liquid film method based on Nusselt theorem. The former uses equivalent Renold number as basic parameter and divided in two regions, but the error is too large while the Renold number were too high or too low. The other method uses liquid film Renold number and calculates in three different regions. It gives more reliable results, but the calculated film coefficient is a temporal value that can't represent the average value. The author has compared various methods and gave an improved suggestion against the problems.