Magneto-hydrodynamic (MHD) micropump of nanofluids in a rotating microchannel under electrical double-layer effect
Pranab Kumar Mondal, Somchai Wongwises
Abstract
We investigate the electroosmosis of nanofluid in a rotating microfluidic channel under the influence of an applied magnetic field. We bring out the rotation-induced complex flow dynamics in the channel as modulated by the nanoparticle driven modifications in the viscous drag. In particular, we observe the flow reversal at the center of the channel, emerging from an intricate competition among different forcings under consideration. We identify the critical rotation Reynolds number, signifying the critical strength of channel rotation relative to the viscous resistance to the flow, for which the flow reversal at the channel center sets in. We demonstrate that the strength of the flow reversal for higher rotation Reynolds number decreases, since higher rotation Reynolds number breaks the interparticle interactions, leading to an enhancement in the effective viscosity of the fluid. Finally, we explain the consequential effects of colloidal suspensions of nanoparticle as realized through the particle concentration and agglomeration size on the alterations in the volume transport rates in the channel.