Numerical study of droplet sorting in an asymmetric Y-junction microfluidic by BEM and LS method

In this study, passive migration of droplet flowing through an asymmetric Y-junction microchannel has been numerically studied by two different numerical methods. The channel geometry consists a straight mother channel and two branched channels with different values of channel length, channel width, and bifurcation angle. In the first part of our study, we apply the boundary element method to numerically solve the integral equation of the Brinkman's differential equation. In the second part, the Navier-Stokes equation coupled with level-set function has been numerically solved by COMSOL Multiphysics. The numerically results obtained from both models are compared to each other. The effect of the droplet radius, dynamics viscosity of droplet, bifurcation angle, width ratio and length ratio of daughter channels on the droplet migration have been numerically investigated. Numerical results indicate that the critical offset distance increases by increasing the bifurcation angle and length ratio. We have found a good agreement between two numerical methods.