Abstract:

Microfluidic technology characterized by microscale process enhancement has the characteristics of high mass and heat transfer efficiency, rapid reaction rate, small reactor size, high controllability and easy amplification, making it be applied in various aspects. Among them, in the field of fluid mixing, microfluidic channels can enhance the mass transfer between multiphase fluids, realize the rapid mixing of samples, and thus intensify the reaction processes. The common methods used for enhancing mixing can be roughly divided into three categories: changing the type of main channels at the junction of side channels (such as from T-junction to co-axial flow-focusing), changing the internal structure of microchannels (such as from normal channels to channels with internal baffles), and altering the flow type of fluids (such as from laminar flow to Taylor flow). This review analyzes the design and principles of different types of microfluidic channels, describes the mixing enhancement effect of different types of microfluidic channels, and introduces the application of microfluidic channels in the preparation of functional materials such as nanoparticles. Microfluidic process enhancement technology provides a safer, more controllable, more efficient and continuous reactor for traditional chemical technology. In the future, continuous and automatic microfluidic desktop factory systems will be more widely used for process intensification.

Key words: microfluidic technology, microchannels, multiphase flow, mass transfer, mixing enhancement

摘要：

以微尺度过程强化为特征的微流控技术具有传质传热效率高、反应速率快、反应器尺寸小、可控性高以及易于放大等特点，被广泛应用于各个方面。其中，在流体混合领域，微流控技术所采用的微通道能够增强多相流体之间的传质，实现样品的快速混合，从而强化反应过程。常用的增强混合的方法可分为改变各通道结合处的通道类型（如从T型变到同轴流动聚焦）、改变通道内部结构（如从普通微通道变为含内部挡板微通道）以及改变流体的流形（如从层流变为泰勒流）三种。本文主要介绍了近年来微尺度过程强化技术在微流控通道设计方面的研究进展，分析了不同类型微流控通道的设计及原理，简述了不同类型微流控通道的混合增强效果，并介绍了微流控通道在制备纳米颗粒等功能材料方面的应用。未来，精细化、集成化且制造简单的微流控装置将会在过程强化中得到更充分的应用。

关键词: 微流控技术, 微通道, 多相流, 传质, 混合增强