十字型微通道内液液两相流体动力学特性OA

The periodic geometric structure of cross-shaped microchannels can induce random flow field structures in microscale liquid-liquid two-phase flow,thus demonstrating broad application prospects in process intensification of micro-chemical systems such as micro-reaction,micro-absorption and so on.A numerical model for liquid-liquid two-phase flow in cross-shaped microchannels was established via the VOF-CSF(volume of fluid-continuum surface force)method,and further the influences of continuous phase flow rate,droplets diameter,the viscosity ratio of continuous phase to dispersed phase as well as the interfacial tension coefficient on two-phase hydrodynamic characteristics were quantitatively investigated.The results show that the periodic structures of gradually expanding-contracting in cross-shaped microchannels maintains the deformed droplets in a dynamic stretching-compression equilibrium,primarily consisting of three distinct stages regarding expansion state,intermediate state and contraction state.Based on the variation laws of droplets interface deformation coefficient with influence factors,the prediction correlations for droplets interface deformation coefficient are developed with several dimensionless numbers.Besides,large continuous phase flow rate and droplet diameter can change the vortex patterns inside the droplets.The increased interfacial tension results in a transition of the number of the internal vortex from two to six.However,the vortex structure remains insensitive to the variations in the viscosity ratio of continuous phase to dispersed phase.The obtained results can provide a scientific guidance for the rational design of liquid-liquid two-phase flow process in cross-shaped microchannels.