Numerical Study Of Liquid-liquid Mass Transfer And Phase Separation In Microchannel

Microreactor has been priority subject due to the excellent performance in heat and mass transfer. For extraction and biphasic reactions, especially the fast reaction system, it is the key to achieve rapid phase separation, subsequently leading to the popular of microseparator and the rapidly growing of micro structured separation.The VOF model and the free surface tracing approach was used to simulate the generation process and development of slug flow in curved channel, double T-channel,and expansion channel. We analyzed the flow field within slugs and proved the the existence of internal circulation. We selected the entrance angle of 60°Y-shape microchannel as the model, and investigated the influence of operating parameters on the two phase pressure drop including different slug velocities, channel diameters,wall wettability and geometry structure. The profile of wall shear stress and the positive correlation between slug superficial velocity and shear stress were studied.What’s more, the effects of operated and physical parameters on phase separation performance based on the pressure balance model, including phase ration, lengths of side channels ration, wettability, and surface tension and so on. Meanwhile, the distribution process of slug flow in vertical T-shape channel was shown. Finally, we manipulated the CFD simulation method and FLUENT software integrated with UDF to simulate the transfer process and the reinforcement process by reactions within liquid-liquid slug flow.Through the study of the post-processing of FLUENT software simulation results,the results show that the two-phase pressure drop increased with increasing slug flow velocity or decreasing diameters. We also found that different slug velocities, channel diameters, wall wettability and surface tension have pronounced influences on the phase separation performance.A fixed interface slug unit approach was applied to simulate the mass transfer process in aqueous/organic phase system. The simulated results show that increased slug velocity, phase ration and diffusion coefficients resulted in the increased mass transfer coefficient. The Hatta number was calculated to judge the speed of the rection.The intensification of mass transfer process by reaction was quantified by theenhancement factor. In all, the simulated results agreed well with the experimental results to validate the simplification model to simulate the single-component mass transfer process. At last, we investigated the concentration profile of butyl-acetate in the aqueous phase within the whole microchannel by the fix frame simulation.