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A generalised model for electro-osmotic flow in porous media

Simona Di Fraia (Dipartimento di ingegneria, Universita degli Studi di Napoli Parthenope, Napoli, Italy)
P. Nithiarasu (School of Engineering, Swansea University, Swansea, UK)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 15 August 2019

Issue publication date: 21 November 2019

189

Abstract

Purpose

This study aims at developing a comprehensive model for the analysis of electro-osmotic flow (EOF) through a fluid-saturated porous medium. To fully understand and exploit a number of applications, such a model for EOF through porous media is essential.

Design/methodology/approach

The proposed model is based on a generalised set of governing equations used for modelling flow through fluid saturated porous media. These equations are modified to incorporate appropriate modifications to represent electro-osmosis (EO). The model is solved through the finite element method (FEM). The validity of the proposed numerical model is demonstrated by comparing the numerical results of internal potential and velocity distribution with corresponding analytical expressions. The model introduced is also used to carry out a sensitivity analysis of the main parameters that control EOF.

Findings

The analysis carried out confirms that EO in free channels without porous obstruction is effective only at small scales, as largely discussed in the available literature. Using porous media makes EO independent of the channel scale. Indeed, as the channel size increases, the presence of the charged porous medium is essential to induce fluid flow. Moreover, results demonstrate that flow is significantly affected by the characteristics of the porous medium, such as particle size, and by the zeta potential acting on the charged surfaces.

Originality/value

To the best of the authors’ knowledge, a comprehensive FEM model, based on the generalised equations to simulate EOF in porous media, is proposed here for the first time.

Keywords

Citation

Di Fraia, S. and Nithiarasu, P. (2019), "A generalised model for electro-osmotic flow in porous media", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 29 No. 12, pp. 4895-4924. https://doi.org/10.1108/HFF-03-2019-0192

Publisher

:

Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited

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