Abstract: Liquid mixing behaviors inside micro-droplets in the microchannels were visualized by μ-LIF technique. These measurement results were adopted to validate the numerical simulations by a newly developed multi-phase, multi-component Lattice Boltzmann Method (LBM), especially to determine a key parameter in the LBM model. The results showed that the simulation can successfully reveal the detailed mixing phenomena inside the droplets. It was discovered that the droplet deformation along its movement in the microchannels can significantly shorten the distance of mass transfer, and thereafter intensify the mixing process. The wetting property of the dispersed phase had strong influence on the flow pattern when the droplet passed through the complex geometry of the micro-channels. In summary, this work provided a solid foundation for the theoretical investigation of complex flows in micro-reactors.

Key words: microfluidics, microdroplet, micromixing, lattice Boltzmann method, μ-LIF

摘要： 采用μ-LIF技术可视化研究了微通道中液滴内部的组分混合行为，建立了描述多相多组分体系的格子波尔兹曼方法（LBM），通过μ-LIF实验确定了LBM模型关键参数，成功模拟了微通道中液滴内部的混合行为。研究表明，液滴在运动中发生形变可以有效缩短传质距离，实现强化混合的目的。同时，分散相对壁面的润湿性质对复杂结构微通道中液滴流动起着重要作用。本文为微尺度复杂流动行为的研究提供了理论基础，并为微通道的结构设计与优化提供了可靠的方法论。

关键词: 微流体, 微液滴, 微混合, 格子Boltzmann方法, 微激光诱导荧光技术