Emulsion droplet formation in coflowing liquid streams.
Emulsion droplet formation in coflowing liquid streams.
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DOI：
10.1103/physreve.87.013002
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Yongping Chen;Liangyu Wu;Chengbin Zhang
中科院分区：
文献类型：
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作者：
Yongping Chen;Liangyu Wu;Chengbin Zhang
我们研究乳液液滴形成的基础上，使用的体积的流体方法跟踪界面运动的滴注和喷射制度的动态计算流体动力学模拟。模拟再现滴，扩大射流和收缩射流同时在同向流动的微通道中与实验观察在这项工作中。结果表明，滴加方式比喷射方式更有利于制备单分散乳液。我们发现，在滴水和扩大喷射制度，一个下降的崩溃是由较高的压力在颈部的后续和主要的液滴挤压液体进入低压区域，而在缩小喷射制度的崩溃是由于缓慢的速度在后端的槽相对于前端的槽。此外，外部流体的毛细管数和内部流体的韦伯数不仅决定了液滴直径和生成速率，而且还决定了乳化状态。
We investigate emulsion droplet formation in coflowing liquid streams based on a computational fluid dynamics simulation using the volume-of-fluid method to track the interface motion with a focus on the dynamics of the dripping and jetting regimes. The simulations reproduce dripping, widening jetting and narrowing jetting simultaneously in a coflowing microchannel in agreement with the experimental observations in this work. The result indicates that the dripping regime, rather than the jetting regime, is a favorable way to producing monodisperse emulsions. We find that, in dripping and widening jetting regimes, the breakup of a drop is induced by higher pressure in the neck which squeezes liquid into the lower-pressure region in subsequent and primary droplets, while the breakup in the narrowing jetting regime is due to slow velocity at the back end of the trough with respect to the leading end of the trough. In addition, the capillary number of the outer fluid and the Weber number of the inner fluid not only determine the drop diameter and generation rate but also the regime of emulsification.