Numerical investigation of particle separation in Y-shaped bifurcating microchannels

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. (C) 2020 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.