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Enhanced electroosmotic flow of Herschel-Bulkley fluid in a channel patterned with periodically arranged slipping surfaces
- Source :
- Physics of Fluids. 31:072007
- Publication Year :
- 2019
- Publisher :
- AIP Publishing, 2019.
-
Abstract
- In this paper, we consider the electroosmotic flow (EOF) of a viscoplastic fluid within a slit nanochannel modulated by periodically arranged uncharged slipping surfaces and no-slip charged surfaces embedded on the channel walls. The objective of the present study is to achieve an enhanced EOF of a non-Newtonian yield stress fluid. The Herschel-Bulkley model is adopted to describe the transport of the non-Newtonian electrolyte, which is coupled with the ion transport equations governed by the Nernst-Planck equations and the Poisson equation for electric field. A pressure-correction-based control volume approach is adopted for the numerical computation of the governing nonlinear equations. We have derived an analytic solution for the power-law fluid when the periodic length is much higher than channel height with uncharged free-slip patches. An agreement of our numerical results under limiting conditions with this analytic model is encouraging. A significant EOF enhancement and current density in this modulated channel are achieved when the Debye length is in the order of the nanochannel height. Flow enhancement in the modulated channel is higher for the yield stress fluid compared with the power-law fluid. Unyielded region develops adjacent to the uncharged slipping patches, and this region expands as slip length is increased. The impact of the boundary slip is significant for the shear thinning fluid. The results indicate that the channel can be cation selective and nonselective based on the Debye layer thickness, flow behavior index, yield stress, and planform length of the slip stripes.
- Subjects :
- Fluid Flow and Transfer Processes
Physics
business.industry
Mechanical Engineering
Computational Mechanics
Herschel–Bulkley fluid
Mechanics
Slip (materials science)
Computational fluid dynamics
Condensed Matter Physics
01 natural sciences
Control volume
010305 fluids & plasmas
Open-channel flow
Physics::Fluid Dynamics
symbols.namesake
Mechanics of Materials
0103 physical sciences
symbols
Electrohydrodynamics
010306 general physics
business
Slipping
Debye length
Subjects
Details
- ISSN :
- 10897666 and 10706631
- Volume :
- 31
- Database :
- OpenAIRE
- Journal :
- Physics of Fluids
- Accession number :
- edsair.doi...........951c53ac39856fceb9f461d1e1b54015