Joule heating and Soret effects on an electro-osmotic viscoelastic fluid flow considering the generalized Phan-Thien–Tanner model

Hernández, Arturo Vera; Mora, A.; Arcos, J.; Bautista, O.

doi:10.1063/5.0146034

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…However, the steady EOF of Newtonian fluids in various microcapillary geometric domains, such as the slit parallel plate [7,8], cylindrical capillary [9,10], T-shape [11], rectangular [12,13], annulus [14,15], semicircular [16], and sector [17] microchannel cross-sections, have been the main focus of EOF research. There has been relatively little research done on the EOF of non-Newtonian fluids, especially viscoelastic fluids [18][19][20][21][22][23]. And, just recently, experimental and numerical research revealed that the EOFs of non-Newtonian fluids are time-dependent and exhibit instabilities.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Time–Periodic Electroosmotic Flow of Viscoelastic Fluid through a Short Constriction Microchannel

Ji,

Qian,

Parker

et al. 2023

Micromachines

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Electroosmotic flow (EOF) is of utmost significance due to its numerous practical uses in controlling flow at micro/nanoscales. In the present study, the time–periodic EOF of a viscoelastic fluid is statistically analyzed using a short 10:1 constriction microfluidic channel joining two reservoirs on either side. The flow is modeled using the Oldroyd-B (OB) model and the Poisson–Boltzmann model. The EOF of a highly concentrated polyacrylamide (PAA) aqueous solution is investigated under the combined effects of an alternating current (AC) electric field and a direct current (DC) electric field. Power-law degradation is visible in the energy spectra of the velocity fluctuations over a wide frequency range, pointing to the presence of elastic instabilities in the EOF. The energy-spectra curves of the velocity fluctuations under a DC electric field exhibit peaks primarily beneath 20 Hz, with the greatest peak being observed close to 6 Hz. When under both DC and AC electric fields, the energy spectra of the velocity fluctuations exhibit a peak at the same frequency as the AC electric field, and the highest peak is obtained when the frequency of the AC electric field is near 6 Hz. Additionally, the frequency of the AC electric field affects how quickly the viscoelastic EOF flows. Higher flow rates are obtained at relatively low frequencies compared to under the DC electric field, and the greatest flow rate is found close to 6 Hz. But as the frequency rises further, the flow rate falls. The flow rate falls to a level below the DC electric field when the frequency is sufficiently high.

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Section: Introductionmentioning

confidence: 99%

Numerical Study of the Time–Periodic Electroosmotic Flow of Viscoelastic Fluid through a Short Constriction Microchannel

Ji,

Qian,

Parker

et al. 2023

Micromachines

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The effect of asymmetric zeta potentials on the electro-osmotic flow of a generalized Phan–Thien–Tanner fluid

Ribau,

Ferrás,

Morgado

et al. 2024

J Eng Math

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Electrokinetic flows driven by electro-osmotic forces are especially relevant in micro and nano-devices, presenting specific applications in medicine, biochemistry, and miniaturized industrial processes. In this work, we integrate analytical solutions with numerical methodologies to explore the fluid dynamics of viscoelastic electro-osmotic/pressure-driven fluid flows (described by the generalized Phan–Thien–Tanner (gPTT) constitutive equation) in a microchannel under asymmetric zeta potential conditions. The constitutive equation incorporates the Mittag–Leffler function with two parameters ($$\alpha $$ α and $$\beta $$ β ), which regulate the rate of destruction of junctions in a network model. We analyze the impact of the various model parameters on the velocity profile and observe that our newly proposed model provides a more comprehensive depiction of flow behavior compared to traditional models, rendering it suitable for modeling complex viscoelastic flows.

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Effect of sinusoidal heated blocks on electroosmotic flow mixing in a microchannel with modified topology

2023

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The present study is focused on micromixing enhancement techniques for electroosmotic flows in a modulated microchannel with a modified topology by utilizing heated blocks on the surface of the microchannel. The heated blocks carry higher temperatures as compared to the other portions of the channel wall, resulting in a sharp variation in the temperature of the fluid. The species transport is governed by the Nernst–Planck equation in a modified form by adding a thermo-electrochemical migration term due to the temperature variation in the ions, justifying the electrochemical equilibrium conditions. The fluid considered for the study is non-Newtonian and is governed by a power-law model. The Navier–Stokes equations, along with the thermal energy equation, are simulated numerically in a coupled form utilizing a finite volume-based semi-implicit method for the pressure-linked equation algorithm to interpret the behavior of the electric potential distribution, the external electric field, the flow field, the temperature distribution, and the species concentration, which are the major contributors for the mixing efficiency. The numerically simulated results are varied with the analytical results for the simple electroosmotic flow in the microchannel, indicating that the mixing efficiency can be enhanced by increasing the temperature of the heated blocks. Due to the thermo-electrochemical migration, ions are redistributed along the heated blocks, oscillating the flow velocity by creating vortices, resulting in the mixing enhancement. The effects of the geometrical parameters, the Debye–Hückel parameter, the temperature gradient, the power-law index, and the Nusselt number are elaborated for the effective flow rate and micromixing. The mixing efficiency is found to be optimum for higher temperature gradients and higher power-law indices. The net throughput analysis that combines the geometrical modulation and wall temperature variation will aid in improving the design and fabrication of microfluidic mixers.

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Joule heating and Soret effects on an electro-osmotic viscoelastic fluid flow considering the generalized Phan-Thien–Tanner model

Cited by 4 publications

References 35 publications

Numerical Study of the Time–Periodic Electroosmotic Flow of Viscoelastic Fluid through a Short Constriction Microchannel

Numerical Study of the Time–Periodic Electroosmotic Flow of Viscoelastic Fluid through a Short Constriction Microchannel

The effect of asymmetric zeta potentials on the electro-osmotic flow of a generalized Phan–Thien–Tanner fluid

Effect of sinusoidal heated blocks on electroosmotic flow mixing in a microchannel with modified topology

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