Numerical study of the vortex‐induced electroosmotic mixing of non‐Newtonian biofluids in a nonuniformly charged wavy microchannel: Effect of finite ion size

Abstract

We propose a micromixer for obtaining better efficiency of vortex induced electroosmotic mixing of non-Newtonian bio-fluids at a relatively higher flow rate, which finds relevance in many biomedical and biological applications. To represent the rheology of non-Newtonian fluid, we consider the Carreau model in this study, while the applied electric field drives the constituent components in the micromixer. We show that the spatial variation of the applied field, triggered by the topological change of the bounding surfaces, upon interacting with the non-uniform surface potential gives rise to efficient mixing as realized by the formation of vortices in the proposed micromixer. Also, we show that the phase-lag between surface potential leads to the formation of asymmetric vortices. This behavior offers better mixing performance following the appearance of undulation on the flow pattern. Finally, we establish that the assumption of a point charge in the paradigm of electroosmotic mixing, which is not realistic as well, under-predicts the mixing efficiency at higher amplitude of the non-uniform zeta potential. The inferences of the present analysis may guide as a design tool for micromixer where rheological properties of the fluid and flow actuation parameters can be simultaneously tuned to obtain phenomenal enhancement in mixing efficiency.

Analysis of thermo-hydraulic and entropy generation characteristics for flow through ribbed-wavy channel

“…In this context, researchers have commonly used two methods for heat transfer enhancement; namely, active and passive ones. The passive method includes surface modifications such as corrugation at the channel wall, using baffles, blocks, twisted or helical tape (Jaferian et al , 2019; Li and Ake Sunden, 2018; Mereu et al , 2013; Tiwari and Moharana, 2019c; Zhang and Liu, 2020; Nandi and Chattopadhyay, 2013, 2014; Mehta et al , 2021), nanofluid and highly conductive porous media (Mehta and Pati, 2021a; Mehdi et al , 2014; Kameswaran et al , 2014; Bhowmick et al , 2021). While the active method needs external perturbation for flow with external sources such as electric or magnetic fields other than the pumping power.…”

Passive solute separation in AC electroosmosis including surface charge‐coupled hydrodynamic slip effects

“…Finally, significant asymmetry in the slip and potential BCs is favored when COPH is desired, as the tidal displacement and Womersley number can be lowered to more practical values for implementation. Future work may be directed toward incorporating non‐Newtonian rheology [23,24,40–43] into the present theory, and examining how COPH of passive solutes is affected by the nonlinear viscosity or viscoelasticity of the electrolyte when subject to asymmetric slip and potential BCs with the apparent hydrodynamic slip being dependent on the surface charging conditions.…”

Experimental and Numerical Investigation of a Novel Spiral Micromixer with Sinusoidal Channel Walls

“…As mentioned, the flow continuity leads to the formation of two counter-rotating vortices, i.e., Dean vortices. To quantitatively evaluate the Dean flow, the dimensionless Dean number is calculated as follows [28,29]:…”