Dense Suspension Inertial Microfluidic Particle Theory (DENSE-IMPACT) Model for Elucidating Outer Wall Focusing at High Cell Densities

TL;DR

This paper introduces a new multiphase model for inertial microfluidics that explains how particles focus at the outer wall at high concentrations, challenging existing theories.

Contribution

The study develops a novel multiphase model incorporating lift forces and particle interactions to explain high-density particle focusing behavior.

Findings

Model accurately predicts outer wall focusing at high concentrations

Numerical simulations match experimental observations

Focusing shift governed by lift force to interaction ratio

Abstract

Inertial microfluidics has been limited to dilute particle concentrations due to defocusing (spreading out) at high particle concentrations. We observe a counterintuitive shift of focusing to the outer curved wall under high concentration flow, which contradicts the existing particle focusing theory. We developed a multiphase model incorporating lift forces and particle-particle interactions to explain this behaviour. Numerical simulations validated by experimental data reveal the shift is governed by the ratio of the lift force strength to that of particle interaction frequencies.