Journal of the Taiwan Institute of Chemical Engineers ( IF 5.5 ) Pub Date : 2022-01-03 , DOI: 10.1016/j.jtice.2021.104193 Yanjun Deng 1 , Weixi Guo 1 , Chunying Zhu 1 , Taotao Fu 1 , Youguang Ma 1
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Background
To improve the coalescence efficiency of droplets in microchannel, a lantern-shaped expansion chamber is proposed to facilitate droplets coalescence.
Methods
A high-speed digital camera was used to study the coalescence process and the mechanism of droplet coalescence was analyzed based on the liquid film draining model.
Findings
The existence of shrinkage mouth could prolong the contact time of droplets and accordingly promote droplet coalescence. The drainage time of continuous phase liquid film decreases with the increase of superficial flow velocity and droplet size, but increases with increasing dispersed phase viscosity. The film drainage time for contact coalescence, squeeze coalescence and tail coalescence increases successively. There exists a minimum critical capillary number Camin and a maximum critical capillary number Camax, and coalescence can occur only when Camin < Ca < Camax. The correlations for predicting the minimum critical capillary number and the maximum critical capillary number are proposed.
中文翻译：
带有灯笼形膨胀室的 T 型接头微通道中两个液滴的聚结动力学
背景
为了提高微通道中液滴的聚结效率，提出了一种灯笼形的膨胀室来促进液滴的聚结。
方法
采用高速数码相机研究液滴聚结过程，基于液膜排水模型分析液滴聚结机理。
发现
缩口的存在可以延长液滴的接触时间，从而促进液滴的聚结。连续相液膜的排水时间随着表观流速和液滴尺寸的增加而减少，但随着分散相粘度的增加而增加。接触聚结、挤压聚结和尾部聚结的膜排水时间依次增加。存在最小临界毛细管数Ca min和最大临界毛细管数Ca max，只有当Ca min < Ca < Ca max时才会发生聚结. 提出了预测最小临界毛细管数和最大临界毛细管数的相关性。
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