Electroviscous Effects in the Electrolyte Liquid Flow Through Asymmetrically Charged Non-Uniform Slit Microfluidic Device

In this work, a pressure-driven, fully developed flow of electrolyte liquid through an asymmetrically charged contraction-expansion slit microchannel is investigated numerically to understand the electroviscous effects. A finite element method (FEM) is used to solve the governing equations, such as Poisson’s, Nernst-Planck, and Navier-Stokes equations, to obtain the flow fields, i.e., total electrical potential, ion concentration, induced electric field strength, velocity and pressure fields for \(3\le K\le 9\) , \(4\le S_\text {t}\le 16\) , and \(0\le S_\text {r}(=S_\text {b}/S_\text {t})\le 2\) . Results show that the electroviscous correction factor (i.e., ratio of apparent to physical viscosity) increases maximally by 20.78% with overall charge-asymmetry ( \(0\le S_\text {r}\le 2\) ) at \(K=3\) and \(S_\text {t}=16\) .