Rotational electrohydrodynamics of a non-Newtonian fluid under electrical double-layer phenomenon: the role of lateral confinement

Abstract

We investigate the transient analysis of the transport features of a non-Newtonian fluid in a rotating microfluidic channel as modulated by the electrical double-layer effect. We use the power-law model to describe rheology of the non-Newtonian fluid in this study. We bring out the rotational force-induced development of the secondary flows inside the channel, taking the effects of the lateral confinement into account. We show that the consideration of lateral confinement into the analysis gives rise to a complex flow dynamics, allowing the formation of double-vortex structures as well as the sister vortexes in the flow field. In particular, we show that the sister vortexes formed in the flow field exhibit different senses of rotations under the influence of the electrical forcing, leading to a potential enhancement in mixing in microfluidic channel. Also, we show the variation of the volume flow rate through the channel for different cases and unveil the secondary flow-induced alteration in the device throughput. We believe that the inferences obtained from this analysis may improve the design of miniaturized systems/devices, typically used for the transportation of bio-fluids, which are largely non-Newtonian in nature, in a rotating platform.