The Taylor flow characteristic and mass transfer in curved T-microchannels

Mass transfer processes in curved microchannels are challenging to measure due to the complex flow structures induced by curved geometries. This study systematically investigates Taylor flow and mass transfer mechanisms in curved T-microchannels using visualization experiments and numerical simulations. Three primary Taylor flow patterns—slug flow, long slug flow, and columnar flow—are observed. A slug length prediction model is developed based on the dispersed phase Reynolds number and the continuous phase capillary number. Comparisons of flow fields in different curved microchannels reveal that curvature effectively disrupts the symmetric internal circulation within the slug, shifting it toward the slug head and splitting it into multiple secondary circulations. This disruption enhances radial mixing and mass transfer within the slug. By introducing mixing efficiency and the Dean number, this study quantifies the influence of channel curvature radius, number of bends, and two-phase flow velocity on flow enhancement and mass transfer. Results indicate that smaller curvature radii, a greater number of bends, and higher dispersed phase volume fractions intensify secondary flow within the channel cross section, thereby promoting mass transfer. Additionally, pressure drop measurement demonstrates that microchannels with more bends and smaller curvature radii correspond to higher energy dissipation. Based on comprehensive numerical and experimental results, a broadly applicable and highly accurate mass transfer prediction model is established using the Dean number, two-phase Reynolds number, and dispersed phase capillary number. This study provides theoretical guidance for optimizing microchannel designs and furthering the application of microchannel reactors in fine chemical processes and related fields.