Numerical investigation of particle separation in Y-shaped bifurcating microchannels

Abstract

In this study the Zweifach-Fung effect is investigated in a Y-shaped bifurcation when the clearance between the rigid spherical particle and the walls is small compared to both channel’s and particle’s radii. Single- and two-particle systems are studied using resolved computational fluid dynamics coupled to discrete element method to obtain a two-dimensional map of the initially positioned particles that would enter each child branch. In all cases, the path selection of the sphere depends on its two-dimensional positioning far from the bifurcation region in the parent channel. Increasing the flow rate ratio or decreasing the Reynolds number intensifies the Zweifach-Fung bifurcation effect in a single-particle system. Similarly, in two-particle systems where non-contact particle–particle interaction is present, decreasing the particle-to-particle distance reduces the bifurcation effect, while changing the Reynolds number has the same influence as in the single-particle systems. The results provide insight for optimizing the flow characteristics in bifurcating microchannels to separate the suspended particles.