CFD simulation of droplet splitting at microfluidic T-junctions in oil–water two-phase flow using conservative level set method

Abstract

Droplet splitting is an important feature of droplet-based microfluidic systems used in chemical engineering, life sciences, biotechnology, biomedical engineering, cosmetic, food industries, etc. as it has various advantages over continuous flow systems. The purpose of this work is to utilize computational fluid dynamics-based model to hasten the fabrication and design process by simulating time-dependent data as droplets flow through a channel and split at a T-junctions. Two-phase conservative level set method has been used to investigate the mechanism of droplet formation and splitting of the droplets at T-junctions. Primary simulations were performed to investigate the formation mechanism of droplet at upstream T-junction, and thus, model was validated by comparing the simulated results with the results reported in the literature. The model was extended to simulate the droplet splitting mechanism at the downstream T-junctions. Conditions of droplets breaking and non-breaking were also determined using various flow rates in case of simple bifurcation channel. Capillary number (Ca = µcu/σ) varied from 0.007 to 0.13. Different flow patterns and splitting of droplets were also observed in the run and branch channels for a wide range of water volume fraction of 0.18–0.7 by varying the mixture velocity from 0.0036 to 0.052 m/s. The simulation results were compared with the experimental data provided in the literature and found a good agreement with the same.