Inertial migration of rigid spherical and non-spherical particles

Partha S. Goswami, Atul M. Bhagat, Mahesh
Investigation of particle migration in a confined channel has become an important area of research . The main objective is to find out the fundamental mechanism of migration from macro to micro geometry and to investigate the effect of different parameters like particle and fluid Reynolds numbers, ratios of the particle to channel length scales and particle to fluid density ratio. The other important aspect is to deploy that fundamental understanding in developing miniaturized macro or micro devices for particle separation. It has been observed that cross stream migration of the particle happens even at a very low Reynolds number; suggests the importance of the inertial term in the equation of motion which is basically responsible to create the cross stream lift force on the particle. Magnitude and direction of this force strongly depend on the particle location within the confined geometry. Particle migrates to an equilibrium position in the wall normal direction where net lift force is zero.
In the present investigation we have mimicked the moving particle system using stationary particle simulation with moving fluid and wall and investigated lift force on the neutrally and non-neutrally buoyant particles using finite element method. Effect of particle shapes for a wide range of Reynolds number and ratios of particle to channel length scales have been investigated. Analysis of the lift force give insight on the equilibrium positions of the particles with non-uniform shape. The effect of multi particle interactions on the distribution of the lift force and the equilibrium positions has also been investigated.