Electro-osmotic flow of couple stress fluids in a microchannel propagated by peristalsis

Tripathi, D; Yadav, A; Beg, OA

Abstract

A mathematical model is developed for electro-osmotic peristaltic pumping of a non-Newtonian liquid in a deformable micro-channel. Stokes’ couple stress fluid model is deployed to represent realistic working liquids. The Poisson-Boltzmann equation for electric potential distribution is implemented owing to the presence of an electrical double layer (EDL) in the micro-channel. Using long wavelength, lubrication theory and Debye-Huckel approximations, the linearized transformed dimensionless boundary value problem is solved analytically. The influence of electro-osmotic parameter (inversely proportional to Debye length), maximum electro-osmotic velocity (a function of external applied electrical field) and couple stress parameter on axial velocity, volumetric flow rate, pressure gradient, local wall shear stress and stream function distributions is evaluated in detail with the aid of graphs. The Newtonian fluid case is retrieved as a special case with vanishing couple stress effects. With increasing couple stress parameter there is a significant elevation in axial pressure gradient whereas the core axial velocity is reduced. An increase in electro-osmotic parameter induces both flow acceleration in the core region (around the channel centreline) and also enhances axial pressure gradient substantially. The study is relevant to simulation of novel smart bio-inspired space pumps, chromatography and medical microscale devices.

Citation

Tripathi, D., Yadav, A., & Beg, O. (2017). Electro-osmotic flow of couple stress fluids in a microchannel propagated by peristalsis. European Physical Journal Plus, 132(4:173), https://doi.org/10.1140/epjp/i2017-11416-x

• Journal Article Type: Article
• Acceptance Date: Feb 20, 2017
• Online Publication Date: Apr 14, 2017
• Publication Date: Apr 14, 2017
• Deposit Date: Mar 10, 2017
• Publicly Available Date: Apr 14, 2018
• Journal: European Physical Journal Plus
• Electronic ISSN: 2190-5444
• Publisher: EDP Sciences
• Volume: 132
• Issue: 4:173
• DOI: https://doi.org/10.1140/epjp/i2017-11416-x
• Publisher URL: http://dx.doi.org/10.1140/epjp/i2017-11416-x
• Related Public URLs: http://epjplus.epj.org/