微通道内气-液弹状流动及传质特性研究进展

摘要

Gas-liquid slug flow (also termed as Taylor flow) is a flow pattern characterized by the alternate movement of elongated bubbles and liquid slugs. Gas-liquid slug flow operation in microchannels has been found important implications in the enhancement of gas-liquid reactions due to its advantages such as easy control, uniform bubble and slug size, narrowed residence time distribution as well as enhanced radial mixing. This review presents the basic conceptions and recent research progress on flow and mass transfer characteristics during the gas-liquid slug flow in microchannels. The gas bubble formation mechanisms, the corresponding bubble and liquid lengths, and mass transfer during bubble formation are summarized. For regular slug flow in the main section of microchannels, several important aspects are addressed including bubble cross-sectional shape and liquid film profile, internal liquid recirculation and leakage flow through the gutters, gas-liquid mass transfer coefficients and coupling phenomena between flow and mass transfer in physical and chemical absorption processes. Finally, an outlook is given for future research directions in this field.%气-液弹状流，又称 Taylor 流，是一种以长气泡和液弹交替形式流动的流动形态。微通道内气-液弹状流因其气泡与液弹尺寸分布均一、停留时间分布窄、径向混合强等优点，是一种适于强化气-液反应的理想流型。本文首先介绍了微通道内气泡的生成机理、气泡和液弹长度，以及气泡生成阶段的传质特征。其次系统综述了主通道中弹状流动及传质过程的研究进展，包括气泡形状与液膜厚度、液弹内循环和泄漏流特征、气-液传质系数的测量与预测，以及物理与化学吸收过程中的传质特性等方面内容。最后阐述了当前研究的不足并展望了气-液弹状流的研究方向。