A numerical study on a macroscopic Stokes number based on shear-induced interparticle collisions in a micro-separator/classifier

In the present study a macroscopic Stokes number Stks is newly proposed for efficient operation of a micro-separator/classifier. The Stks is a ratio of particle relaxation time to interval of shear-induced interparticle collisions. The collision interval is estimated based on a representative shear rate and average particle concentration passing through an outer plane defined at the end of arc microchannel. The device efficiency is evaluated in terms of reduced particle recovery Rc to the outer plane. It is shown that the Stks would be useful for predicting a maximum feed concentration to be handled with a highest Rc.