Dynamics of double emulsion break-up in three phase glass capillary microfluidic devices
Dynamics of double emulsion break-up in three phase glass capillary microfluidic devices
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DOI：
10.1016/j.jcis.2015.03.032
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发表时间：
2015-07-15
影响因子：
9.9
通讯作者：
Ekanem, Ekanem E.
中科院分区：
文献类型：
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作者：
Nabavi, Seyed Ali;Gu, Sai;Ekanem, Ekanem E.
采用不可压缩三相轴对称流体体积-连续表面力（VOF-CSF）数值模型研究了三维玻璃毛细管微流控装置中复合射流的夹断现象。该模型表现出良好的协议与实验滴生成，并能够预测形成的核/壳液滴滴在滴，缩小喷射和扩大喷射制度。在滴落和加宽喷射状态下，颈缩螺纹上游端周围涡流的存在有利于射流破碎。在窄化喷射区域没有观察到涡流，并且由于同轴螺纹下游端的速度比上游端的速度高而发生夹断。在所有状态下，内射流在外射流之前破裂，防止内液滴泄漏到外流体中。由于螺纹外表面处的剪切水平最高，颈缩区域在变窄喷射状态下以最大速度移动。然而，在加宽喷射状态下，颈部在其断裂之前向下游行进最长距离。(C)2015年，作者。爱思唯尔公司出版这是一个在CC BY许可证下的开放获取文章（http：//creativecommons.org/licenses/by/4.0/）。
Pinch-off of a compound jet in 3D glass capillary microfluidic device, which combines co-flowing and countercurrent flow focusing geometries, was investigated using an incompressible three-phase axisymmetric Volume of Fluid-Continuum Surface Force (VOF-CSF) numerical model. The model showed good agreement with the experimental drop generation and was capable of predicting formation of core/shell droplets in dripping, narrowing jetting and widening jetting regimes. In dripping and widening jetting regimes, the presence of a vortex flow around the upstream end of the necking thread facilitates the jet break-up. No vortex flow was observed in narrowing jetting regime and pinch-off occurred due to higher velocity at the downstream end of the coaxial thread compared to that at the upstream end. In all regimes, the inner jet ruptured before the outer jet, preventing a leakage of the inner drop into the outer fluid. The necking region moves at the maximum speed in the narrowing jetting regime, due to the highest level of shear at the outer surface of the thread. However, in widening jetting regime, the neck travels the longest distance downstream before it breaks. (C) 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).