Electroosmotic flow in a slit nanochannel with superhydrophobic walls

De, Simanta; Bhattacharyya, S.; Hardt, Steffen

doi:10.1007/s10404-015-1660-7

Cited by 16 publications

(4 citation statements)

References 31 publications

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“…One of the objectives of this study is to demonstrate the volume flow augmentation in the channel by placing periodic slip planes. Enhanced fluid transport in a channel is also an important aspect in the context of microfluidic devices (De et al, 2015). We have adopted the two-phase model in which the effects of Brownian diffusion and thermophoresis of nanoparticles are taken into account.…”

Section: Two-phase Model For Mixed Convectionmentioning

confidence: 99%

Two-phase model for mixed convection and flow enhancement of a nanofluid in an inclined channel patterned with heated slip stripes

Dutta

Bhattacharyya

Pop

2021

HFF

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Purpose The purpose of this study is to analyze the heat transfer and flow enhancement of an Al2O3-water nanofluid filling an inclined channel whose lower wall is embedded with periodically placed discrete hydrophobic heat sources. Formation of a thin depletion layer of low viscosity over each hydrophobic heated patch leads to the velocity slip and temperature jump condition at the interface of the hydrophobic patch. Design/methodology/approach The mixed convection of the nanofluid is analysed based on the two-phase non-homogeneous model. The governing equations are solved numerically through a control volume approach. A periodic boundary condition is adopted along the longitudinal direction of the modulated channel. A velocity slip and temperature jump condition are imposed along with the hydrophobic heated stripes. The paper has validated the present non-homogeneous model with existing experimental and numerical results for particular cases. The impact of temperature jump condition and slip velocity on the flow and thermal field of the nanofluid in mixed convection is analysed for a wide range of governing parameters, namely, Reynolds number (50 ≤ Re ≤ 150), Grashof number ( 103≤Gr≤5×104), nanoparticle bulk volume fraction ( 0.01≤φb≤0.05), nanoparticle diameter ( 30≤dp≤60) and the angle of inclination ( −60°≤σ≤60°). Findings The presence of the thin depletion layer above the heated stripes reduces the heat transfer and augments the volume flow rate. Consideration of the nanofluid as a coolant enhances the rate of heat transfer, as well as the entropy generation and friction factor compared to the clear fluid. However, the rate of increment in heat transfer suppresses by a significant margin of the loss due to enhanced entropy generation and friction factor. Heat transfer performance of the channel diminishes as the channel inclination angle with the horizontal is increased. The paper has also compared the non-homogeneous model with the corresponding homogeneous model. In the non-homogeneous formulation, the nanoparticle distribution is directly affected by the slip conditions by virtue of the no-normal flux of nanoparticles on the slip planes. For this, the slip stripes augment the impact of nanoparticle volume fraction compared to the no-slip case. Originality/value This paper finds that the periodically arranged hydrophobic heat sources on the lower wall of the channel create a significant augmentation in the volume flow rate, which may be crucial to augment the transport process in mini- or micro-channels. This type of configuration has not been addressed in the existing literature.

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Section: Two-phase Model For Mixed Convectionmentioning

confidence: 99%

Two-phase model for mixed convection and flow enhancement of a nanofluid in an inclined channel patterned with heated slip stripes

Dutta

Bhattacharyya

Pop

2021

HFF

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“…As a result, electroosmotic flow (EOF) is feasible for managing flow in microfluidic devices. In the literature, many interesting studies on the electrokinetic flow of non-Newtonian fluids and Newtonian fluids with regard to different geometrical configurations have been published (Das and Chakraborty 2006;Monazami and Manzari 2007;Afonso et al 2009;Misra et al 2011;De et al 2015;An et al 2022a).…”

Section: Introductionmentioning

confidence: 99%

A theoretical analysis of rotating electromagnetohydrodynamic and electroosmotic transport of couple stress fluid through a microchannel

Siva,

Jangili,

Kumbhakar

2024

Z Angew Math Mech

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The main motivation behind this research work is the electroosmotic flow (EOF), which characterizes the movement of charged particles in a fluid when subjected to an external electric field, which offers precise control over fluid movement without mechanical components. The study of bio‐fluids in rotating microfluidic platforms is becoming much more significant. Hence, it is important to discuss the non‐Newtonian fluids in such environments. This paper analytically investigates the hydrodynamic characteristics of combined electromagnetohydrodynamic (EMHD) and EOF transport of non‐Newtonian fluid through a rotating microchannel with Navier‐slip boundary conditions at the walls. The couple stress fluid model is considered a non‐Newtonian fluid in the flow domain. The linearized Poisson‐Boltzmann equation is considered inside the electric double layer (EDL). The modified Stokes equation is governed by a combined imposed magnetic and EOF field. Closed form expressions are obtained for electrical potential, flow velocity, and volume flow rate in the channel using analytical methods. The dependence of rotating electromagnetic flow velocity and flow rates on appropriate parameters is explained. It is found that the rotational flow velocity displays an opposite pattern when the couple stress parameter and electric field intensity parameters are varied due to the influence of channel rotation. It is also found that the secondary flow rate ratio is amplified with the Hartmann number and slip length parameter, due to the stronger impact of the non‐Newtonian behaviour than the Newtonian situation on the volume flow rate at a relatively higher rotational value. The findings of this study may aid in the design and analysis of practical thermal micro/nano‐equipment for transporting biofluids.

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“…The objective of this work is to investigate the microchannel geometry and electric force influence on the ionic concentration. Moreover, D Simanta et al (2015) [13] studied an electroosmotic flow under slip conditions on the walls of a slit nanochannel with alternating charged patches and uncharged patches neglecting the shear stress, by solving numerically the system of coupled Navier-Stokes and Poisson-Nernst-Planck equations, considering arbitrary displacement between the upper and lower wall patterns. The obtained results are expressed by a dimensionless number E f , which represents the ratio of the average flow velocity through the channel to the average flow velocity through a plane-walled channel under the same induced wall potential.…”

Section: Introductionmentioning

confidence: 99%

Viscoelectric effect analysis in an electroosmotic flow with microchannel wall slip

et al. 2023

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In the present work, we developed a numerical analysis for an electroosmotic flow circulating in a rectangular microchannel considering electrolyte viscosity as a function of the induced electric field; which is also reflected in the slip condition imposed on the system walls, since the slip length is a function of the fluid viscosity. It should be clarified this is an entirely hydrodynamic problem, and for this reason there are no induced pressure gradients, because we are in the presence of a purely electroosmotic flow, where the fluid motion is due only to electrokinetic forces. Based on these comments, the problem is centered on high induced potentials, enabling viscoelectric effect analysis in the electroosmotic flow, which leads to significant increases in velocity and volumetric flow profiles compared to the case where the viscosity is a constant and there is no slip condition. Due to analytical analysis limitations, we implemented a dimensionless equation scheme defined by the continuity equation, the momentum equations in the x and y direction, the Poisson-Boltzmann equation, and the charge conservation equation to obtain the velocity and volumetric flow rate profiles mentioned above. This model is described in its variational form in order to implement the finite element technique using free software, FreeFem++.

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Electroosmotic flow in a slit nanochannel with superhydrophobic walls

Cited by 16 publications

References 31 publications

Two-phase model for mixed convection and flow enhancement of a nanofluid in an inclined channel patterned with heated slip stripes

Two-phase model for mixed convection and flow enhancement of a nanofluid in an inclined channel patterned with heated slip stripes

A theoretical analysis of rotating electromagnetohydrodynamic and electroosmotic transport of couple stress fluid through a microchannel

Viscoelectric effect analysis in an electroosmotic flow with microchannel wall slip

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