Mass transfer intensification of slug flow by interfacial deformation at low flow rate in the microchannels with periodic expansion units

Liquid-liquid slug flow has great application potential in many fields. The effective intensification of mass transfer is an important impetus for its wider application. However, it still lacks a method which can intensify its mass transfer at low flow-rate without slug breakup. Hereon, the periodic expansion microchannel is used to induce the interface deformation of the droplets in slug flow to strengthen mass transfer. Concentration field obtained by experimental analysis, and velocity field obtained through numerical simulation are used to investigate the influence of expansion structure on the mass transfer mechanism of liquid-liquid slug flow. The regulating mechanism of mass transfer is disclosed by investigating the effect of operating conditions on the volumetric mass transfer coefficient kLa and intensification factor E. Optimized E can reach up to 1.5. Introducing expansion structures could intensify the mass transfer of slug flow in a microchannel with low energy consumption.