From droplets to waves: periodic instability patterns in highly viscous microfluidic flows
From droplets to waves: periodic instability patterns in highly viscous microfluidic flows
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DOI：
10.1017/jfm.2019.1009
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发表时间：
2020-03-25
影响因子：
3.7
通讯作者：
Cubaud, Thomas
中科院分区：
文献类型：
--
作者：
Hu, Xiaoyi;Cubaud, Thomas
实验研究了粘度差异较大的微流体-液-液多相流从液滴到波动的过渡过程。采用基于周期模式分析的统一方法研究了大范围流速和粘度对比下的分散流型和分离流型之间的关系，包括滴流、喷射流、毛细波、惯性波和岩心-环空流动。我们根据重复细胞的波长、频率和速度来研究每个流态的形态和动力学，以阐明它们的联系，并基于无因次控制参数开发预测能力。我们特别证明了模式选择取决于过渡时液滴和波的传播速度。我们还研究了微流体破波现象与韧带和液滴形成的波峰在毛细管波和惯性波制度。这项工作扩展了在微通道中观察到的传统多相流形式，并展示了在受限微系统中利用界面波动力学分散高粘性材料的新途径。
We experimentally study the transition from droplet to wave regimes in microfluidic liquid-liquid multiphase flows having large differences in viscosity. A unified approach based on periodic pattern analysis is employed to study relationships between dispersed and separated flow regimes, including dripping, jetting, capillary waves, inertial waves and core-annular flows over a wide range of flow rates and viscosity contrasts. We examine the morphology and dynamics of each flow regime based on wavelength, frequency and velocity of repeating unit cells to elucidate their connections and to develop predictive capabilities based on dimensionless control parameters. We demonstrate in particular that pattern selection is contingent upon the propagation velocity of droplets and waves at the transition. We also investigate microfluidic wave breaking phenomena with the formation of ligaments and droplets from wave crests in both capillary and inertial wave regimes. This work expands conventional multiphase flow regimes observed in microchannels and shows new routes to disperse highly viscous materials using interfacial waves dynamics in confined microsystems.