Technical Papers and Presentations

Inertial focusing of particles in a fluid flow is a physical effect induced by inertial forces already happening at the micro-fluidic scale. COMSOL Multiphysics® has provided an implementation of the drag and lift forces to compute this effect for a constant parallel-wall fluid channel and provided a good benchmark model in 2D. We aim in this paper to show it is possible to solve fluid channels with slowly varying cross-sections (i.e. non-parallel walls) in 3D and to solve the problem with a multi-physics coupling to the thermal field. This enables a new era of diagnostic tools to be designed in an optimal way, by ensuring both model validation in 3D for non-parallel fluid channel walls and to extrapolate results in coupled physics where no experiment has yet been conducted. In this work we provide some results of the 3D models we implemented and the comparison to the experimental/numerical data available in recent literature. We then extrapolate results when we co-simulate both the thermal field and the coupled fluid-particle interaction. The goal of this work is to prove we can reliably use COMSOL Multiphysics® to make a model and program a simple COMSOL® app for designing and optimizing a 3D-microfluidic apparatus to focus particles in a fluid stream. This model enables a new design workflow of more complex and better performing diagnostic micro-fluidic applications.