Effect of interface deformation on hydrodynamics of liquid–liquid two-phase flow in a confined microchannel
Effect of interface deformation on hydrodynamics of liquid–liquid two-phase flow in a confined microchannel
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DOI：
10.1016/j.cej.2021.131956
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发表时间：
2022
影响因子：
15.1
通讯作者：
Taoxian Zhang;S.K.M. Ting;Yingjuan Zhang;Dawei Pan;Weixing Huang;Bo Li
中科院分区：
文献类型：
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作者：
Taoxian Zhang;S.K.M. Ting;Yingjuan Zhang;Dawei Pan;Weixing Huang;Bo Li
采用VOF-CSF模型模拟研究了界面变形对受限微通道内液液两相流流型、回流、涡量和液膜厚度的影响。通过系统研究直径比、粘度比、连续相流量和界面张力系数对液滴界面变形的影响，实现了对液滴界面变形的定量控制，并根据力场特征全面揭示了相应的界面变形机理。特别是阐明了液滴内部两种典型的流场结构，以定量区分液液两相流流型，即弹状流和推塞流，并研究了流场结构的转变规律。弹状流在液滴内部表现为两个旋涡，压差力和剪切力是主要作用力。然而，在推流中，观察到了两个额外的二次循环涡，其中拉普拉斯压力力起着重要的作用。此外，还发现涡量大小与界面变形系数呈正相关。在考虑了多个变量、范围较大的情况下，建立了多个无量纲数预测液膜厚度的通用关联模型。研究结果可为设计强化传热传质和反应过程的液液两相流微系统提供理论指导。
Effect of interface deformation on flow patterns, recirculation flow, vorticity magnitude, and liquid film thickness of liquid–liquid two-phase flow in a confined microchannel was investigated via a simulation method using the VOF-CSF model. The quantitative control over the droplet interface deformation is achieved by systematically studying the influences of diameter ratio, viscosity ratio, continuous phase flow rate as well as interfacial tension coefficient, and further, the corresponding interface deformation mechanisms are comprehensively revealed based on the force field characteristics. Especially, two typical flow field structures inside the droplet are clarified to quantitatively distinguish the liquid–liquid two-phase flow patterns, namely slug and plug flow, and the transition law of flow field structure is also investigated. The slug flow is characterized by two vortices inside the droplet and the dominant forces are the differential pressure force and shearing force. However, in plug flow, two additional secondary recirculating vortices are observed, in which the Laplace pressure force plays a significant role. Moreover, it is also found that the vorticity magnitude is positively correlated with the interface deformation coefficient. Taking multiple variables with a wide range into account, a universal correlation model for predicting the liquid film thickness with several dimensionless numbers is established. Finally, the obtained results could provide theoretical guidance for designing a liquid–liquid two-phase flow microsystem to enhance heat and mass transfer and reaction process.