Simulation of non-spherical particles in curved microfluidic channels

Abstract

The paper analyzes the migration of non-spherical particles in curved micro-channels. Inertial migration combined with Dean drag results in a reduced set of stable focusing positions in specific regions of the cross section of the channel. These are studied using fully resolved transient simulations of particulate flows in rectangular curved ducts with oblate and prolate particles at a bulk Reynolds number of 100 and dilute particle concentrations. The simulations were conducted with four particles in a periodic domain, instead of only one, as common practice, to investigate the particle interaction. It is observed that the focusing positions are different for the non-spherical particles compared to those obtained with spherical ones. Not only non-spherical particles focus closer to the upper and lower walls, but also their focusing position is closer to the half width of the channel. Furthermore, the migration velocity along the cross section is compared between particle shapes. Results show that all shapes lead to a significant change in migration velocity between outer and inner halves of the channel. This effect is substantially more pronounced for non-spherical particles and is observed for the first time here. It offers an independent possibility for particle separation according to shape.