Electroosmotic Mixing of Non-Newtonian Fluid in a Microchannel with Obstacles and Zeta Potential Heterogeneity

• Published in: Micromachines (Basel) Vol. 12; no. 4; p. 431
• Main Authors: Mei, Lanju, Cui, Defu, Shen, Jiayue, Dutta, Diganta, Brown, Willie, Zhang, Lei, Dabipi, Ibibia K
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14.04.2021; MDPI
• Subjects: Aqueous solutions; Barriers; Boundary conditions; Computational fluid dynamics; Electric double layer; Electric fields; Electrolytes; electroosmotic flow; Heterogeneity; heterogeneous surface potential; Ion transport; Mathematical models; Microchannels; Micromixing; micromixing performance; Newtonian fluids; Non Newtonian fluids; power-law fluid; Reynolds number; Rheological properties; Rheology; Thickness; Velocity; Viscosity; wall obstacle; Zeta potential; heterogeneous surface potential; wall obstacle; electroosmotic flow; power-law fluid; micromixing performance
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi12040431

This paper investigates the electroosmotic micromixing of non-Newtonian fluid in a microchannel with wall-mounted obstacles and surface potential heterogeneity on the obstacle surface. In the numerical simulation, the full model consisting of the Navier-Stokes equations and the Poisson-Nernst-Plank equations are solved for the electroosmotic fluid field, ion transport, and electric field, and the power law model is used to characterize the rheological behavior of the aqueous solution. The mixing performance is investigated under different parameters, such as electric double layer thickness, flow behavior index, obstacle surface zeta potential, obstacle dimension. Due to the zeta potential heterogeneity at the obstacle surface, vortical flow is formed near the obstacle surface, which can significantly improve the mixing efficiency. The results show that, the mixing efficiency can be improved by increasing the obstacle surface zeta potential, the flow behavior index, the obstacle height, the EDL thickness.