T形微通道结构中液液两相流动与传质规律

Liquid-liquid two-phase flow and mass transfer in T-shaped micro-channel network

对单级和双级T形微通道结构中水和甲苯两相流动与传质进行了实验与模拟,拍摄了两相流动流型变化,通过测量醋酸在水和甲苯两相的分配获得了T形微通道中液液两相传质系数。采用VOF流体力学模型模拟了T形微通道中弹状流的形成和变化过程,准确预测了弹状尺寸。研究发现,无论流动处于弹状流还是并行流,在保持相同停留时间条件下,双级T形微通道结构中总的体积传质系数及萃取效率明显高于单级。结果说明,含有多级T形结构的分形树状仿生网络能够有效地提高液液两相间的传质速率,多级T形网络是一种高效的微萃取构型。

A series of high-resolution CFD simulations as well as experiments were performed to investigate flow and mass transfer of liquid-liquid phases in single and double T-shaped micro-channel networks. Two stable flow patterns were observed, namely slug flow and parallel flow. Liquid-liquid mass transfer rates were measured based on distribution of acetic acid in water and toluene system. Moreover, volume of fluid model （VOF） was used to simulate the generation and development of slug flow and predict slug length. Simulation results agreed well with experimental data. At the same residence time, mass transfer coefficients and extraction efficiency were higher in the double T-mixer than the single one. Tree-shaped networks containing multi-stage T-shaped micro-channel greatly enhanced liquid-liquid mass transfer in micro-channels, and this kind of network was a powerful micro-extraction configuration.