Effects of channel wall wettability on gas-liquid dynamics mass transfer under Taylor flow in a serpentine microchannel

The wall wettability of microchannels plays an important role in the gas-liquid mass transfer dynamics under Taylor flow. In this study, we regulated the contact angle of the wall surface through surface chemical grafting polymerization under controlled experimental conditions. The dynamic changes of CO2 bubbles flowing along the microchannel were captured by a high-speed video camera mounted on a stereo microscope, whilst a unit cell model was employed to theoretically investigate the gas-liquid mass transfer dynamics. We quantitatively characterized the effects of wall wettability, specifically the contact angle, on the formation mechanism of gas bubbles and mass transfer process experimentally. The results revealed that the gas bubble velocity, the overall volumetric liquid phase mass transfer coefficients (kLa), and the specific interfacial area (a) all increased with the increase of the contact angle. Conversely, gas bubble length and leakage flow decreased. Furthermore, we proposed a new modified model to predict the gas-liquid two-phase mass transfer performance, based on van Baten's and Yao's models. Our pro-posed model was observed to agree reasonably well with experimental observations.(c) 2023 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

The study investigates the impact of wall wettability on the formation of gas bubbles and mass transfer process in microchannels. The results show that an increase in contact angle leads to higher gas bubble velocity, overall volumetric liquid phase mass transfer coefficients, and specific interfacial area, while reducing gas bubble length and leakage flow. A modified model is proposed to predict the gas-liquid mass transfer performance and agrees well with experimental observations.