Effects of Aspect Ratio on Flow and Condensation in Rectangular Microchannels

被引：0

作者：

Wu C.-X. ^{[1
]}

Li J.-M. ^{[1
]}

机构：

[1] Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing

来源：

Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | 2018年 / 32卷 / 06期

关键词：

Aspect ratio; Condensation; Gregorig effect; Injection flow; Microchannel;

D O I：

10.3969/j.issn.1003-9015.2018.00.018

中图分类号：

学科分类号：

摘要：

A transient numerical model based on volume of fluid for flow and condensation in rectangular microchannels was proposed. A separated model for vapor-liquid flow was adopted for velocity inlet considering entrance effect of velocity and liquid film thickness. The numerical mode was verified by data from literature, and condensation flow and heat transfer of R32 in three rectangular microchannels (aspect ratios of 2:3, 1:1 and 3:2) were numerically studied (annular, injection flow, bubbly flow and shrinking bubbly). The results of gas-liquid phase distribution on the channel sections and wall heat flux distribution show that with aspect ratio away from 1:1, the non-uniformity of condensate film distribution increases, which reinforces the Gregorig effect and hence enhances heat transfer. The enhanced heat transfer makes the Weber number and Capillary number of tail vapor core smaller, which leads to the injection flow further towards the inlet, and has lower occurrence frequency of the vapor slug detachment. The calculation results show that the flow and condensation process are significantly affected by the rectangular aspect ratio. Compared with square channels, strict rectangular channels are more conducive in heat transfer and can inhibit gas-liquid interface fluctuation. © 2018, Editorial Board of Journal of Chemical Engineering of Chinese Universities". All right reserved."

引用

页码：1264 / 1273

页数：9

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