CFD analysis of electroviscous effects in electrolyte liquid flow through heterogeneously charged uniform microfluidic device
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| Format: | Preprint |
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2023
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| author | Dhakar, Jitendra Bharti, Ram Prakash |
| author_facet | Dhakar, Jitendra Bharti, Ram Prakash |
| contents | This study has numerically investigated the charge-heterogeneity effects in the electroviscous flow of symmetric ($1$:$1$) electrolyte liquid through a uniform slit microfluidic device. The Poisson's, Nernst-Planck (N-P), Navier-Stokes (N-S), and continuity equations are solved using the finite element method (FEM) to obtain the flow fields, such as total electrical potential ($U$), excess charge ($n^\ast$), induced electric field strength ($E_\text{x}$), and pressure ($P$) fields for following conditions: inverse Debye length ($2\le K\le 20$), surface charge density ($4\le \mathit{S_\text{1}}\le 16$), and surface charge-heterogeneity ratio ($0\le \mathit{S_\text{rh}}\le 2$). Results have shown that the total potential ($|ΔU|$) and pressure ($|ΔP|$) drop maximally increase by 99.09% (at $K=20$, $\mathit{S_\text{1}}=4$) and 12.77% (at $K=2$, $\mathit{S_\text{1}}=8$), respectively with overall charge-heterogeneity ($0\le \mathit{S_\text{rh}}\le 2$). Electroviscous correction factor (i.e., the ratio of effective to physical viscosity) maximally enhances by 12.77% (at $K=2$, $\mathit{S_\text{1}}=8$), 40.98% (at $\mathit{S_\text{1}}=16$, $\mathit{S_\text{rh}}=1.50$), and 41.35% (at $K=2$, $\mathit{S_\text{rh}}=1.50$), with the variation of $\mathit{S_\text{rh}}$ (from 0 to 2), $K$ (from 20 to 2), and $\mathit{S_\text{1}}$ (from 0 to 16), respectively. Further, a simple pseudo-analytical model is developed to estimate the pressure drop in the electroviscous (EV) flow, accounting for the influence of charge-heterogeneity based on the Poiseuille flow in the uniform channel. This model predicts the pressure drop $\pm$2-4% within the numerical results. The robustness and simplicity of this model enable the present numerical results for engineering and design aspects of microfluidic applications. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2312_16032 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | CFD analysis of electroviscous effects in electrolyte liquid flow through heterogeneously charged uniform microfluidic device Dhakar, Jitendra Bharti, Ram Prakash Fluid Dynamics This study has numerically investigated the charge-heterogeneity effects in the electroviscous flow of symmetric ($1$:$1$) electrolyte liquid through a uniform slit microfluidic device. The Poisson's, Nernst-Planck (N-P), Navier-Stokes (N-S), and continuity equations are solved using the finite element method (FEM) to obtain the flow fields, such as total electrical potential ($U$), excess charge ($n^\ast$), induced electric field strength ($E_\text{x}$), and pressure ($P$) fields for following conditions: inverse Debye length ($2\le K\le 20$), surface charge density ($4\le \mathit{S_\text{1}}\le 16$), and surface charge-heterogeneity ratio ($0\le \mathit{S_\text{rh}}\le 2$). Results have shown that the total potential ($|ΔU|$) and pressure ($|ΔP|$) drop maximally increase by 99.09% (at $K=20$, $\mathit{S_\text{1}}=4$) and 12.77% (at $K=2$, $\mathit{S_\text{1}}=8$), respectively with overall charge-heterogeneity ($0\le \mathit{S_\text{rh}}\le 2$). Electroviscous correction factor (i.e., the ratio of effective to physical viscosity) maximally enhances by 12.77% (at $K=2$, $\mathit{S_\text{1}}=8$), 40.98% (at $\mathit{S_\text{1}}=16$, $\mathit{S_\text{rh}}=1.50$), and 41.35% (at $K=2$, $\mathit{S_\text{rh}}=1.50$), with the variation of $\mathit{S_\text{rh}}$ (from 0 to 2), $K$ (from 20 to 2), and $\mathit{S_\text{1}}$ (from 0 to 16), respectively. Further, a simple pseudo-analytical model is developed to estimate the pressure drop in the electroviscous (EV) flow, accounting for the influence of charge-heterogeneity based on the Poiseuille flow in the uniform channel. This model predicts the pressure drop $\pm$2-4% within the numerical results. The robustness and simplicity of this model enable the present numerical results for engineering and design aspects of microfluidic applications. |
| title | CFD analysis of electroviscous effects in electrolyte liquid flow through heterogeneously charged uniform microfluidic device |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2312.16032 |