Mass transfer intensification and mechanism analysis of gas–liquid two-phase flow in the microchannel embedding triangular obstacles

Abstract

An effective mass transfer intensification method was proposed by embedding different triangular obstacles to improve the gas–liquid mass transfer efficiency in microchannel. The influences of triangle obstacles configuration, obstacle interval and flow rate on the volumetric mass transfer coefficient, pressure drop and energy consumption were investigated experimentally. The enhancement factor was used to quantify the mass transfer enhancement effect of triangle obstacles. It was found that the isosceles or equilateral triangle obstacles are superior to the rectangular obstacles. The maximum enhancement factor of equilateral triangle obstacles was 2.35. Considering comprehensively mass transfer enhancement and energy consumption, the isosceles triangle obstacle showed the best performance, its maximum enhancement factor was 2.1, while the maximum pressure drop increased only 0.41 kPa (22%) compared to the microchannel without obstacles. Furthermore, a micro-particle image velocimetry (micro-PIV) was utilized to observe the flow field distribution and evolution, in order to understand and analyze the enhancement mechanism. The micro-PIV measurement indicated that the obstacle structure could induce the formation of vortex, which promotes convective mass transfer and thins the flow boundary layer, accordingly, the gas–liquid mass transfer efficiency is remarkably improved. This study can provide theoretical guidance and support for the design and optimization of microchannel with triangular obstacles.