Numerical simulation of the Marangoni flow on mass transfer from single droplet with different Reynolds numbers

The interfacial flow and mass transfer of multicomponent droplets remain an unsolved basic problem, although multicomponent droplets are widely used in droplet microfluidics, fine chemicals. In this paper, Level-set method is used to capture the phase interface, and the evolution of Marangoni convection under different Reynolds numbers is investigated by CFD simulation. The influence of Marangoni effect on the macroscopic characteristics such as droplet velocity and concentration decay rate under different motion states are reported, and the divergence of velocity at the interface is statistically analyzed at microscopic level. The results reveal that the droplet Reynolds number has a great influence on the development of Marangoni convection in life and space; The local divergence can clearly reflect the influence of flow structure and flow velocity on interphase material transport; The Marangoni vortices are multi-scale, and the interphase mass transfer containing the Marangoni effect is non-Gaussian and oscillating, which similar to turbulence. Compared to previous research, this work complements a lot of micro information of the interface Marangoni flow, and deeply discusses the competition between Marangoni and internal circulation flow in droplets under different Reynolds numbers.