Enhanced droplet formation in a T-junction microchannel using electric field: A lattice Boltzmann study
Enhanced droplet formation in a T-junction microchannel using electric field: A lattice Boltzmann study
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使用电场增强 T 形连接微通道中的液滴形成：晶格玻尔兹曼研究
DOI：
10.1063/5.0100312
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发表时间：
2022-07
影响因子：
4.6
通讯作者：
Siyu Zhao
中科院分区：
文献类型：
--
作者：
Liu Zhaomiao;Fanming Cai;Yan Pang;Yanlin Ren;Nan Zheng;Rui Chen;Siyu Zhao
电场驱动液滴形成技术可以有效地提高液滴形成通量和控制液滴尺寸，对于微尺度液滴在生物制药和化学分析中的应用具有重要意义。采用三维格子Boltzmann方法（3DLBM）结合漏电介质模型，研究了电场作用下T型微通道内液滴的形成特性，重点分析了电毛细数、流量比和粘度比对液滴尺寸的影响.结果表明，随着电毛细数的增加，非均匀分布的电场力使分散相发生拉伸，形成泰勒锥，并使两种液体界面处的剪切力增大，以克服表面张力。这有助于从挤压到滴落的过渡，并减小液滴尺寸。在高流量比下，增加电毛细数会导致分散相与壁面之间产生钉扎效应，从而加剧连续相对分散相颈部的挤压，导致液滴尺寸显著减小。随着粘度比的增大，电场力引起的涡流阻力减小，电场效应将主导液滴的形成过程。
The electric field-driven droplet formation technique can effectively improve the formation throughput and control the droplet size, which is important for the application of microscale droplets in biopharmaceuticals and chemical analysis. In this paper, the droplet formation characteristics in T-junction microchannels under the action of electric field are investigated by coupling a three-dimensional lattice Boltzmann method (3 D LBM) with the leaky dielectric model, focusing on the effects of electric capillary number, a flow ratio, and a viscosity ratio on the droplet size. It is shown that as the electrical capillary number increases, the non-uniformly distributed electric force stretches the dispersed phase to form a Taylor cone and increases shear force at the interface of the two liquids to overcome the surface tension force. This facilitates the transition from squeezing to dropping and reduces the droplet size. At high flow ratios, increasing the electric capillary number leads to a pinning effect between the dispersed phase and the wall, which intensifies the compression of continuous phase on the neck of dispersed phase, resulting in a significant decrease in the droplet size. As the viscosity ratio increases, the vortex resistance caused by electrical force decreases, and thus, the electric field effect will dominate the droplet formation process.