Distribution of gas-liquid two-phase slug flow in parallel micro-channels with different branch spacing
Distribution of gas-liquid two-phase slug flow in parallel micro-channels with different branch spacing
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DOI：
10.1016/j.ijheatmasstransfer.2018.12.040
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发表时间：
2019-04
影响因子：
5.2
通讯作者：
Yanchu Liu;Shuangfeng Wang
中科院分区：
文献类型：
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作者：
Yanchu Liu;Shuangfeng Wang
采用实验方法，研究了6种平行微通道中气液弹状流在分支间距分别为0.8 mm（2d）、4 mm（10 d）和12 mm（30 d）时的相分布。平行微通道由一个水力直径为0.48 mm的集管和六个水力直径为0.40 mm的分支通道组成，均为矩形截面。整个试验节段均由PMMA机加工，以便于流动可视化。氮气和0.03重量%十二烷基硫酸钠（SDS）溶液在环境压力和室温下被用作测试流体。在气液进口表观速度分别为0.28 ≤JG≤ 33.3m/s和0.008 ≤JL≤ 2.52m/s的范围内，生成了泡状、段塞状、段塞-环空和环空流型图。进行了弹状流的相分布实验。采用高速记录技术对平行微通道内两相流分离的流体动力学过程进行了记录。结果表明，平行通道内两相流的相分布特性与入口条件和通道间距密切相关。此外，在不同的进口流量条件下，分支间距对流动的影响呈现出不同的特点。在低质量流量和干度下，增大分支间距有利于液相向集箱后部通道流动，而在高质量流量和干度下，随着分支间距的增大，前三个通道的供液量增加。特别地，随着分支间距的增加，气体分布也得到改善。最后，建立了一个能够预测平行微通道弹状流液相分布的关联式。
An experimental study was conducted in order to investigate the phase distribution of gas-liquid slug flow in six parallel micro-channels in presence of different branch spacing of 0.8 mm(2d), 4 mm(10d) and 12 mm(30d), respectively. The parallel micro-channels was composed of a header with hydraulic diameter of 0.48 mm and six branch channels with hydraulic diameter of 0.40 mm, all with rectangle cross sections. The entire test section was machined by PMMA to facilitate flow visualization. Nitrogen and 0.03 wt% sodium dodecyl sulfate (SDS) solution at ambient pressure and room temperature were used as the test fluids. A flow-regime map of bubbly, slug, slug-annular and annular was generated, covering the range of gas and liquid inlet superficial velocities of 0.28 ≤JG≤ 33.3 m/s and 0.008 ≤JL≤ 2.52 m/s, respectively. The phase distribution experiments of slug flow were conducted. The fluid dynamics of two-phase flow splitting in parallel micro-channels was captured by high speed recording technique. It was found that the phase distribution characteristics of two-phase flow in parallel channels highly depend on the inlet flow conditions and the distance between channels. Besides, the effect of branch spacing took on distinct characteristics under different inlet flow conditions. At low mass flux and quality, the increase of branch spacing can facilitate the liquid phase to flow into channels at the rear part of the header, while the first three channels are more supplied with liquid as the branch spacing increasing at high mass flux and quality. Specially, an improvement of gas distribution was also observed with the increase of the branch spacing. Finally, a correlation capable of predicting the liquid phase distribution of slug flow in parallel micro-channels was developed.