Numerical Investigation of the Influence of Microchannel Geometry on the Droplet Generation Process

Abstract

Two immiscible fluids flowing in microchannels are essential for microdevices to achieve efficient transfer of fluid reactions and heat, droplet mixing, extraction, and emulsification. In this study, a numerical investigation of the flow regime of droplet generation and the droplet breakup behavior of immiscible fluids (water and oil) in various microchannel structures was undertaken. To predict the influence of the microchannel structure on droplet generation and the breakup process, a two-phase level set method was implemented. The generated droplets were validated with experimental results of the T-shape microchannel structure. The obtained numerical results were in good agreement with the experimental results. Furthermore, the validated model was used to investigate the effect of various types of microchannel structures on droplet generation and breakup behavior. Also, the effects of different viscosities, wetted wall contact angles, surface tension, the size of continuous and dispersed channel widths, and the continuous flow rate for droplet generation and breakup in the microchannel were studied. This work contributes to better understanding of effective microchannel design.

Keywords

• microfluidics
• immiscible fluids
• two-phase flow
• droplet
• channel structure
• level-set method
• generator and breakup