Flow boiling heat transfer and pressure drop characteristics of Isobutane in horizontal channels with twisted tapes
Flow boiling heat transfer and pressure drop characteristics of Isobutane in horizontal channels with twisted tapes
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DOI：
10.1016/j.ijheatmasstransfer.2020.120345
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发表时间：
2020-12
影响因子：
5.2
通讯作者：
Alireza Sarmadian;H. A. Moghaddam;A. Asnaashari;Hossein Ahmadi Nejad Joushani;M. Moosavi;M. S. Islam;S. Saha;Maziar Shafaee
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文献类型：
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作者：
Alireza Sarmadian;H. A. Moghaddam;A. Asnaashari;Hossein Ahmadi Nejad Joushani;M. Moosavi;M. S. Islam;S. Saha;Maziar Shafaee
对扭带作为一种被动式强化两相流换热器传热的方法进行了实验研究。测试蒸发器是一个长度为1000 mm，内径为8.1 mm的水平安装的铜通道。在制冷剂蒸汽质量在0.1-0.8的范围内并且制冷剂质量速度在160-350 kgm-2s-1之间时，使用具有4、10和15的扭曲比的三种扭曲带。选择天然制冷剂异丁烷（R600 a）作为工作流体，因为它是环境友好的。实验结果表明，与普通通道相比，在通道内安装扭带可以提高通道的传热效率和压降。还观察到，对于普通和扭曲的磁带插入通道，传热系数和压力损失的值的增长引起的制冷剂质量速度和蒸汽质量。结果表明，系统性能系数在0.44-1.09之间变化，前提是在特定操作条件下使用扭带作为湍流器是有益的。实验数据表明，存在一个最佳的工质质量流速值，在该值下扭带插入通道的性能最好。
Using twisted tapes as a passive method for heat transfer improvement in a two-phase flow heat exchanger is experimentally studied. The test evaporator is a copper channel with a length of 1000 mm and an internal diameter of 8.1 mm which is installed horizontally. Three twisted tapes with twist ratios of 4, 10, and 15 are used at refrigerant vapor qualities in the range of 0.1–0.8 and refrigerant mass velocities between 160-350 kgm−2s−1. The natural refrigerant Isobutane (R600a) is chosen as the working fluid because it is environmentally friendly. According to the experiments, installing twisted tapes inside the channel augments both heat transfer rate and pressure drops over the plain channel. It is also observed that for both plain and twisted tape inserted channels, the values of heat transfer coefficients and pressure losses grow by giving rise to the refrigerant mass velocity and vapor quality. Results showed that the system performance factor varied between 0.44–1.09 offering that using twisted tapes as a turbulator is beneficial under specific operating conditions. The empirical data showed that there is an optimum value of the working fluid mass velocity at which the performance of twisted tape inserted channels is higher.