Acoustic Behavior of a Dense Suspension in an Inhomogeneous Flow in a Microchannel

Abstract

Bulk relocation of coflowing streams in an acoustic field occurs when there is a mismatch in acoustic impedance between the fluids. In separation of red blood cells from whole blood, for example, this relocation is prevented by ensuring that the central buffer stream has the higher impedance. This study shows that for dense suspensions like blood, in addition to typical full-relocation/zero-relocation regimes, an intermediate partial relocation may occur when the buffer's impedance is not high enough. This establishes the influence of particles in acoustic relocation, and provides a way to split any dense suspension into a concentrated central stream and a dilute side stream.