Electro-osmosis of non-Newtonian fluids in porous media using lattice Poisson–Boltzmann method
[Display omitted] •Electro-osmotic permeability of non-Newtonian fluid varies with external electric field magnitude.•Shear-thinning fluid and shear-thickening fluid exhibit different electro-osmotic permeability dependent on porosity.•Fluids with different properties show different correlations bet...
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Veröffentlicht in: | Journal of colloid and interface science 2014-12, Vol.436 (436), p.186-193 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | [Display omitted]
•Electro-osmotic permeability of non-Newtonian fluid varies with external electric field magnitude.•Shear-thinning fluid and shear-thickening fluid exhibit different electro-osmotic permeability dependent on porosity.•Fluids with different properties show different correlations between permeability and microstructure morphology.
Electro-osmosis in porous media has many important applications in various areas such as oil and gas exploitation and biomedical detection. Very often, fluids relevant to these applications are non-Newtonian because of the shear-rate dependent viscosity. The purpose of this study was to investigate the behaviors and physical mechanism of electro-osmosis of non-Newtonian fluids in porous media. Model porous microstructures (granular, fibrous, and network) were created by a random generation-growth method. The nonlinear governing equations of electro-kinetic transport for a power-law fluid were solved by the lattice Poisson–Boltzmann method (LPBM). The model results indicate that: (i) the electro-osmosis of non-Newtonian fluids exhibits distinct nonlinear behaviors compared to that of Newtonian fluids; (ii) when the bulk ion concentration or zeta potential is high enough, shear-thinning fluids exhibit higher electro-osmotic permeability, while shear-thickening fluids lead to the higher electro-osmotic permeability for very low bulk ion concentration or zeta potential; (iii) the effect of the porous medium structure depends significantly on the constitutive parameters: for fluids with large constitutive coefficients strongly dependent on the power-law index, the network structure shows the highest electro-osmotic permeability while the granular structure exhibits the lowest permeability on the entire range of power law indices considered; when the dependence of the constitutive coefficient on the power law index is weaker, different behaviors can be observed especially in case of strong shear thinning. |
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ISSN: | 0021-9797 1095-7103 |
DOI: | 10.1016/j.jcis.2014.08.048 |