Mass transfer characteristic in the formation stage of gas–liquid segmented flow in microchannel
Mass transfer characteristic in the formation stage of gas–liquid segmented flow in microchannel
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DOI：
10.1016/j.cej.2012.01.054
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发表时间：
2012-03
影响因子：
15.1
通讯作者：
J. Tan;Yangcheng Lu;Jianhong Xu;G. Luo
中科院分区：
文献类型：
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作者：
J. Tan;Yangcheng Lu;Jianhong Xu;G. Luo
本文研究了微通道内气液分段流形成阶段的传质特性。采用具有不同接触角的改良T形连接微通道作为微型器件。首先确定形成的气段塞的长度。开发了一种原位方法来测量传质特性。结果表明，有传质的气段塞初始长度远小于无传质的气段塞初始长度。段塞形成时间在0.2-0.4s范围内，形成阶段的传质可占总转移溶质的30-40%左右。段塞形成阶段的总传质系数在1.4~5.5×10−4m/s范围内。实验结果与扩散模型计算数据的对比表明，气段塞内的再循环流动显着强化了传质，增强因子在5~15范围内。考虑表面更新和气相移动速度的影响，建立了相关方程来预测增强因子。计算数据与实验结果吻合较好。
In this paper, the mass transfer characteristic in the formation stage of gas–liquid segmented flow in microchannel was investigated. Modified T-junction microchannels with differing contact angles were applied as the microdevices. The length of formed gas slug was determined firstly. An in situ method was developed to measure the mass transfer characteristic. The results showed that the initial length of gas slug with mass transfer was much smaller than that without mass transfer. The slug formation time was in the range of 0.2–0.4s and the mass transfer during the formation stage could contribute around 30–40% of the total transferred solute. The overall mass transfer coefficient during the slug formation stage was in the range of 1.4–5.5×10−4m/s. The comparison between the experimental results and the calculated data by diffusion model indicated that the recirculation flow in the gas slug significantly intensified the mass transfer with the enhancement factor in the range of 5–15. A correlation equation was developed to predict the enhancement factor, considering both the influences of the surface renewal and the moving speed of the gas phase. The calculated data was in good coincidence with the experimental results.