Interphase Mass Transfer Between A Single Particle And Extensional Creeping Flow

The fundamental research on transport phenomena(momentum,heat and mass transfer)of a single particle is of great importance in practical application in chemical and process industry.Droplets would deform gradually from prolate to ‘peanut' shape in uniaxial extensional flow,or from oblate to ‘red-blood-cell' shape in biaxial extensional flow.The wall effect between a stationary deformed drop and the modest extensional flow in a cross-intersected channel and the nonlinear flow that exists in industrial rotary devices is very common and plays an important role on particle transport phenomena.Unfortunately,most previous works are dedicated to studying a single spherical particle(bubble,liquid drop,or solid particle)immersed in a simplified linear flow,such as in simple shear flow or in simple extensional flow.In order to explore the complex problems precisely,this work studied numerically(by boundary element method,concentration transformation method)the internal,external,conjugate mass/heat transfer of a spherical/deformable particle immersed in simple/modest/nonlinear extensional creeping flows.For mass transfer from/to a single prolate droplet in simple extensional creeping flow,the effects of Peclet number(1?Pe?1000),capillary number(0?Ca?0.1),viscosity ratio(0.01??? 1),diffusivity ratio(0.1?K?10)and distribution coefficient(0.1?m? 10)on interphase mass transfer processes were examined in terms of numerical simulation.Given Pe,Ca,?,K and m,an empirical correlation with an average relative deviation of 12% was proposed to predict Sherwood number Sh of prolate and spherical droplets suspended in uniaxial extensional creeping flow.For mass transfer from/to a single deformable droplet in the uniaxial and biaxial extensional creeping flow,the empirical correlations were proposed to predict the internal mass transfer rate of a deformable droplet(by adding parameter Ca to represent the deformation of a droplet)in simple extensional flow.For the unsteady conjugate interphase mass transfer between a stationary deformed drop and the modest extensional flow in a cross-intersected channel,the simulation results show that the mass transfer rate,analyzed and characterized by concentration variation and Sherwood number Sh,is affected by Ca,Pe,?,K,m and wall proximity parameter W.For a single liquid drop immersed in a nonlinear extensional creeping flow,the empirical correlations of external mass transfer rate of a single spherical droplet in the nonlinear extensional flow were proposed to predict Sh in the range of 1?Pe?1000and-5?E?10.For that of a spherical solid in the non-linear flow,the empirical correlations of the external mass transfer of a single solid sphere were proposed to predict Sh in the whole range of 1?Pe?100000 and-5?E?10.