The three-dimensional two-phase flow dynamics inside a microfluidic device of complex geometry is simulated using a parallel, hybrid front-tracking/level-set solver. The numerical framework employed circumvents numerous meshing issues normally associated with constructing complex geometries within typical computational fluid dynamics packages. The device considered in the present work is constructed via a module that defines solid objects by means of a static distance function. The construction combines primitive objects, such as a cylinder, a plane, and a torus, for instance, using simple geometrical operations. The numerical solutions predicted encompass dripping and jetting, and transitions in flow patterns are observed featuring the formation of drops, 'pancakes', plugs, and jets, over a wide range of flow rate ratios. We demonstrate the fact that vortex formation accompanies the development of certain flow patterns, and elucidate its role in their underlying mechanisms. Experimental visualisation with a high-speed imaging are also carried out. The numerical predictions are in excellent agreement with the experimental data.

中文翻译：

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使用前跟踪方案模拟复杂微通道几何中不混溶的液-液流动。

使用并行，混合的前跟踪/水平集求解器模拟复杂几何形状的微流体设备内部的三维两相流动动力学。所采用的数值框架规避了通常与在典型的计算流体动力学软件包内构造复杂的几何形状有关的众多网格划分问题。本工作中考虑的设备是通过一个模块构造的，该模块通过静态距离函数定义实体。例如，该结构使用简单的几何运算将原始对象（例如圆柱体，平面和圆环）组合在一起。预测的数值解决方案包括滴落和喷射，并且在宽范围的流量比范围内观察到流动模式的转变，其特征在于液滴，“煎饼”，塞子和喷射的形成。我们证明了涡流形成伴随着某些流动模式的发展这一事实，并阐明了其在其潜在机制中的作用。还进行了具有高速成像的实验可视化。数值预测与实验数据非常吻合。