Electroosmotic Pumping Between Two Immiscible Electrical Conducting Fluids Controlled by Interfacial Phenomena

Abstract

In this study, the isothermal electroosmotic flow of two immiscible electrical conducting fluids within a uniform circular microcapillary was theoretically examined. It was assumed that an annular layer of liquid adjacent to the inside wall of the capillary exists, and this in turn surrounds the inner flow of a second liquid. The theoretical analysis was performed by using the linearized Poisson-Boltzmann equations, and the momentum equations for both fluids were analytically solved. The interface between the two fluids was considered uniform, hypothesis which is only valid for very small values of the capillary number, and shear and Maxwell stresses were considered as the boundary condition. In addition, a zeta potential difference and a charge density jump were assumed at the interface. In this manner, the electroosmotic pumping is governed by the previous interfacial effects, a situation that has not previously been considered in the specialized literature. The simplified equations were nondimensionalized, and analytical solutions were determined to describe the electric potential distribution and flow field in both the fluids. The solution shows the strong influence of several dimensionless parameters, such as μr, εr, w  ,   and sf Q , and 1,2  , on the volumetric flow. The parameters represent the ratio of viscosity, the ratio of electric permittivity of both fluids, the dimensionless zeta potential of the microcapillary wall, the dimensionless charge density jump and charge density between both fluids, and the electrokinetic parameters, respectively.

Effects of Slip and Inclined Magnetic Field on the Flow of Immiscible Fluids (Couple Stress Fluid and Jeffrey Fluid) in a Porous Channel

“…The study of immiscible fluids like Newtonian versus Newtonian, Newtonian versus Non-Newtonian, and/or Non-Newtonian versus Non-Newtonian fluids occurs in industries, manufacturing process, groundwater hydrology, etc. Recently, several researchers studied the flows of immiscible fluids, to mention a few, such as Newtonian fluid-Newtonian fluid or Newtonian-Non-Newtonian fluid (Berg et al [14], Padma Devi and Srinivas [15], Yadav and Sneha [16,17], Deo and Ansari [18], Matias et al [19], Malashetty and Umavathi [20], Ramana Murthy and Srinivas [21], and Punnamchandar and Fekadu [22]) in channel configurations with slip and/or no-slip boundary conditions.…”

Mixing Enhancement of Electroosmotic Flow in Microchannels under DC and AC Electric Field

“…Therefore, the mixing of two different solutions within a microchannel is achieved only by diffusion mechanisms and it will take a very long time (Lim and Lam, 2012). Many microfluidic devices attempt to overcome this disadvantage by passive method or active method (Shamloo et al, 2017;Matías et al, 2018). The passive mixing method does not require external force (Wang et al, 2007).…”

AC two-immiscible-fluid EOF in a microcapillary

“…Moghadam [25] examined the two-fluid electrokinetic flow in a microchannel and obtained analytic solutions for velocity profiles. Other researchers [26,27] investigated the influence of interfacial phenomenon on controlling the EOF pumping of two immiscible fluids. Analytic solutions of transient electroosmotic and pressuredriven flow of two-layer fluids were obtained by Su et al [28] and Gao et al [29] in slit and rectangular microchannels, respectively.…”