Electro-osmosis of electrorheological fluids

Abstract

Electrorheological fluids are suspensions that are characterized by a strong functional dependence of the constitutive behavior of the fluids on the electric field. In this work, we consider electro-osmosis of an electrorheological fluid through a channel where a transverse, nonuniform electric field is spontaneously induced due to the presence of an electric double layer that is manifested due to surface charge density at the channel wall. We reveal a nonlinear interplay between the applied electric field, the induced electric field, and the observed flow profiles, which is fundamentally distinctive from other types of nonlinear electrokinetic effects that have been extensively discussed in the literature, in a sense that here an interaction between the applied electric field, the induced electric field, and the dependence of the rheology on the resultant electric field happens to be the focal source of nonlinearity in the observed phenomena. We analyze the electro-osmotic flow control through the exploitation of a combined nonlinear interplay of the driving electrokinetic forces and the resistive viscous interactions, which gives rise to distinctive flow regimes as compared to those realized in cases of either Newtonian fluids or non-Newtonian fluids having electric-field-independent flow rheology.

Taylor–Couette flow of electrorheological fluids under electrical double layer phenomenon

“…Very recently, however, possible consequences of internally induced electrical field on ER effects have been discussed with particular emphasis on microfluidics and nanofluidics based applications [28]. The generation of an induced electric field, under these circumstances, has primarily been attributed to physicochemical interactions near the solid boundary, leading to the formation of an Electrical Double Layer (EDL).…”

The effect of the finite size of ions and Debye layer overspill on the screened Coulomb interactions between charged flat plates

“…For instance, κ −1 as large as 1 µm was observed in charged colloids of silica in ethanol and deionized water. Although a closed‐form analytical solution of the PB equation in such situations has been deemed infeasible , several approximate analytical solutions of the PB equation or its modified variants have been undertaken for conditions exhibiting the interaction or merging of Debye layers . Philipse et al.…”

Electro-osmosis of nematic liquid crystals under weak anchoring and second-order surface effects

“…Electrokientic transport phenomena of complex fluids through micro-condiment have been elaborately studied in the literature [1][2][3] due to its various applications in biomedical engineering [4,5], energy conversion processes [6,7], environmental sciences and thermal management of electronic packages, to name a few. Emergence of electrokinetic transport of ordered fluids, especially of anisotropic liquid crystal medium, has led to numerous studies in recent times that explores the flow behavior and non-linear effects under the scope of microscale dynamics [8].…”