Generation and evolution of double emulsions in a circular microchannel

Double emulsions are attracting much attention from academic community and industry fields. Emerging microfluidics technology offered new ways to prepare unprecedentedly controllable double emulsions. Here a numerical simulation method, volume of fluid (VOF) technique, was adopted to study the generation and evolution of double emulsions in a circular microchannel, which is helpful for understanding the underlying physics of double emulsion preparation and optimizing the operation conditions. The flow pattern regions where double emulsions existed were found and classified according to dripping and jetting models of double emulsion generation. Velocity fields inside and outside double emulsions were investigated, and several distinct velocity vortexes were observed. Several characteristic parameters involving pressure distribution of fluids and deformation index of double emulsions were studied. At last, preparation of double emulsions with desired configurations, including same inner droplets engulfed by different outer droplets and same outer droplets encapsulating different inner droplets, were explored in depth.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study utilized numerical simulation to investigate the generation and evolution of double emulsions. By analyzing the velocity fields and characteristic parameters, a better understanding of the underlying physics of double emulsion preparation can be achieved.