Abstract:

In order to address the complexity of the process of two-phase flow boiling in pump-assisted separated heat pipe and the poor experimental reproducibility, an experimental apparatus of pump-assisted separated heat pipe was built to study the pressure gradient and heat transfer coefficient of boiling heat transfer for R134a serving as a medium of heat transfer, which were compared with those in open literature. It showed that the integration of pressure gradient by Muller-Steinhagen-Heck correlation fits experimental result well with an error bar below ±10%. Moreover, at vapor quality above 0.1, Mohseni correlation predicts the experimental heat transfer coefficient with an error bar of ±10%, while at vapor quality below 0.1, it does with some error bars above 30%. For the purpose of minimizing the large error bars a modified correlation was built. Efforts of above correlation results were conducted as a reference standard for experimental study, numerical simulation and optimization design of heat pipe system.

Key words: pump-assisted separated heat pipe, gas-liquid flow, flow, boiling, heat transfer, heat transfer coefficient, pressure gradient

摘要：

针对动力型热管内两相流沸腾过程复杂未知,实验复现性差的问题,搭建了动力型热管两相流沸腾传热实验装置,对水平管内R134a工质沸腾传热过程的沿程阻力特性及对流传热系数进行了实验研究,并将获得的实验数据与前人总结的压降、对流传热系数计算关联式进行对比分析。研究表明,Muller-Steinhagen-Heck压降关联式的积分值与实验结果吻合较好,误差在±10%以内;Mohseni关联式在干度大于0.1时所得对流传热系数与实验结果具有较好一致性,误差在±10%以内,但在干度小于0.1时存在较大偏差,部分误差已超30%,为此重新拟合了干度小于0.1时的对流传热系数关联式。该结果可为该类换热器的实验研究、数值模拟及优化设计提供有效的理论参考标准。

关键词: 动力型热管, 气液两相流, 流动, 沸腾, 传热, 对流传热系数, 压降梯度