(416b) Particle Migration in a Liquid-Liquid Stratified Flow in a Microchannel

Inertial focusing is a passive separation technique in an axial flow where particles migrate laterally to equilibrium positions in the presence of finite inertia. These equilibrium positions mainly depend on the two counteracting forces namely the wall lift force and the shear gradient force. The equilibrium positions can be altered by changing the velocity profile of the fluid.

In this work, we model the inertial focusing of a particle in the laminar, liquid-liquid stratified flow in a microchannel. This is used for the separation and recovery of cells from one fluid to the other. The particle is sent through one fluid and due to the shear gradient forces and interfacial forces, the particle may focus into the other fluid or stuck at the interface. Towards this, we develop a 2D model (flow between infinite parallel plates) based on the immersed boundary method together with the level set method to study the hydrodynamics and the particle migration. The effect of fluid and particle properties and the operating conditions (phase holdup and Reynolds number) on the particle migration is analyzed.