Numerical Investigation on the Effect of Variation of Cross-Sectional Shape on Acoustophoresis

Abstract

Acoustophoresis, the technology of manipulating microparticles in a micro-channel using bulk or standing waves, is currently finding interest in bioanalytical and clinical fields for cell handling and manipulation. This work presents the numerical analysis of variation of cross-sectional shape on acoustophoretic parameters. The acoustophoretic forces are included into the model by subsequently solving the first order acoustic fields and the second-order time averaged net flow. This study also considered the effect of variation of channel aspect ratio on various acoustophoretic parameters. Various acoustophoretic parameters focussed are first-order pressure field, first-order acoustic velocity, streaming velocity, streaming pressure and particle trajectories. This study revealed that channels with convex cross sections enable faster manipulation of microparticles. It is also observed that the acoustophoretic parameters get reduced with increase in aspect ratio of the channel. This study also showed that smaller sized particles are more influenced by acoustic streaming induced drag force. It is also understood that particle separation is effective under radiation force and mixing phenomena is pronounced under streaming force.