Inertial focusing of finite-size particles in microchannels

Abstract

At finite Reynolds numbers, Re, particles migrate across laminar flow streamlines to their equilibrium positions in microchannels. This migration is attributed to a lift force, and the balance between this lift and gravity determines the location of particles in channels. Here we demonstrate that velocity of finite-size particles located near a channel wall differs significantly from that of an undisturbed flow, and that their equilibrium position depends on this, referred to as slip velocity, difference. We then present theoretical arguments, which allow us to generalize expressions for a lift force, originally suggested for some limiting cases and Re<<1, to finite-size particles in a channel flow at Re < 20. Our theoretical model, validated by lattice Boltzmann simulations, provides considerable insight into inertial migration of finite-size particles in microchannel and suggests some novel microfluidic approaches to separate them by size or density at a moderate Re.

17 pages, 9 figures

References in corpus (4)

• Inertial migration of a rigid sphere in three-dimensional Poiseuille flow
• Recent advances in the simulation of particle-laden flows
• Direct Measurement of Particle Inertial Migration in Rectangular Microchannels
• Lattice-Boltzmann simulations of the drag force on a sphere approaching a superhydrophobic striped plane

Cited by in corpus (6)

• Inertial migration of neutrally-buoyant particles in superhydrophobic channels
• Lift and drag forces acting on a particle moving with zero slip velocity near a wall
• Inertial migration of oblate spheroids in a plane channel
• Inertial focusing of a dilute suspension in pipe flow
• Instability of particle inertial migration in shear flow
• Drag and lift forces on a rigid sphere immersed in a wall-bounded linear shear flow