Electroosmotic flow of a Phan-Thien–Tanner fluid in a wavy-wall microchannel

Martinez, Luis; Bautista, O.; Escandón, Juan P.; Méndez, F.

doi:10.1016/j.colsurfa.2016.02.036

Cited by 35 publications

(9 citation statements)

References 20 publications

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“…Equations (41)(42)(43)(44) denote the Newtonian case as reported by Middleman 2 and its solution is given below…”

Section: Solution Of Zeroth-order Systemmentioning

confidence: 99%

Mathematical study of viscoelastic polymer during roll-over-web coating

Atif,

Jabeen,

Javed

2023

Journal of Plastic Film & Sheeting

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Roll-coating, also known as roll-to-roll coating or web coating is a continuous and high-speed method used in various industrial applications to apply a thin and uniform layer of material onto a substrate. This process is commonly employed in industries such as electronics, photovoltaic, printing, packaging, and other fields where precise and consistent coating is essential. Here we present an asymptotic analysis of forward roll coating over a rigid substrate for low Weissenberg number viscoelastic fluids. The analysis uses lubrication theory coupled with regular perturbation theory assuming a simplified Phan-Thien-Tanner (SPPT) constitutive equation and small values of the extensibility parameter ε. The analytical expressions of velocity fields, pressure gradient and pressure fields are obtained while the load carrying force, and power input are estimated by numerical solutions (4th order Runge-Kutta). Increases in both Wi and ε increases the pressure gradient in the nip region and increases in viscoelasticity reduce the overall force on the roll. Further, SPTT model predicts 14% lower pressure for [Formula: see text] in the nip region when compared to Newtonian model.

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“…Equations (41)(42)(43)(44) denote the Newtonian case as reported by Middleman 2 and its solution is given below…”

Section: Solution Of Zeroth-order Systemmentioning

confidence: 99%

Mathematical study of viscoelastic polymer during roll-over-web coating

Atif,

Jabeen,

Javed

2023

Journal of Plastic Film & Sheeting

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“…In order to gain more physical insight on our experimental observations, we performed three-dimensional direct numerical simulations of a rigid spherical particle in a polymeric flow modelled by the FENE-P model. This model allows to reach higher Wi in dilute polymer flows than other viscoelastic models such as the Oldroyd-B [52] and better prediction of shear viscosity at high shear rates than Giesekus fluids [53] and Phan-Tien Thanner models [54].…”

Section: Numerical Simulationsmentioning

confidence: 99%

Analogue tuning of particle focusing in elasto-inertial flow

et al. 2021

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We report a unique tuneable analogue trend in particle focusing in the laminar and weak viscoelastic regime of elasto-inertial flows. We observe experimentally that particles in circular cross-section microchannels can be tuned to any focusing bandwidths that lie between the “Segre-Silberberg annulus” and the centre of a circular microcapillary. We use direct numerical simulations to investigate this phenomenon and to understand how minute amounts of elasticity affect the focussing of particles at increasing flow rates. An Immersed Boundary Method is used to account for the presence of the particles and a FENE-P model is used to simulate the presence of polymers in a Non-Newtonian fluid. The numerical simulations study the dynamics and stability of finite size particles and are further used to analyse the particle behaviour at Reynolds numbers higher than what is allowed by the experimental setup. In particular, we are able to report the entire migration trajectories of the particles as they reach their final focussing positions and extend our predictions to other geometries such as the square cross section. We believe complex effects originate due to a combination of inertia and elasticity in the weakly viscoelastic regime, where neither inertia nor elasticity are able to mask each other’s effect completely, leading to a number of intermediate focusing positions. The present study provides a fundamental new understanding of particle focusing in weakly elastic and strongly inertial flows, whose findings can be exploited for potentially multiple microfluidics-based biological sorting applications.

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“…A better fluid mixing can be obtained by making the surfaces of the mixer as corrugated as the flow becomes locally accelerated and decelerated in the converging and diverging passages, respectively. − The electroosmotic flow through a wavy channel establishes a nonuniform distribution of electric field, which is also helpful to create a stirring effect. − Banerjee and Nayak numerically investigated the effects of amplitude, the flow behavior index, and the Debye–Hückel parameter on the mixing characteristics for flow of non-Newtonian fluids through a wavy channel with periodically varying zeta potentials and reported that the increase in amplitude remarkably enhances the mixing efficiency at higher flow behavior indices at the cost of higher pressure drop. Banerjee et al numerically investigated the mixing and flow characteristics for electroosmotic flow through a complex wavy channel and found a threshold value of amplitude for which eddies are formed at the wavy section.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Electroosmotic Mixing in a Wavy Micromixer Using Surface Charge Heterogeneity

Mehta

Pati

2022

Ind. Eng. Chem. Res.

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We investigate the flow and mixing characteristics for an electroosmotic flow through a wavy micromixer using surface charge heterogeneity. The Laplace equation for the external electric field, Poisson–Boltzmann equation for potential distribution, and continuity and momentum equations for fluid flow and species transport equation have been solved by imposing the appropriate boundary conditions using a finite element method-based numerical solver. The results are presented by varying the phase lag of sinusoidal zeta potential between the two walls (Δϕ), Debye parameter (κ), geometrical wave number (n), dimensionless wall amplitude (α), and diffusive Peclet number (Pe). The results reveal that the phase lag has a strong confluence on the flow field and mixing performance together with other physicochemical parameters. The strength of primary flow as well as the size of the recirculation zones increases with Δϕ and κ, and additional recirculation zones are formed in the core of the mixer for Δϕ = 0. The value of mixing efficiency is close to 100% up to a critical value of Pe (Pe Cri), the value of which is greater for the nonuniformly charged surface potential with a nonzero phase lag. For thinner EDL (κ = 150), a fully mixed state based on 90% mixing is achieved up to higher values of Pe with a higher flow rate at Δϕ = π/2 and π. Also, for Δϕ = π/2, the mixing efficiency as well as the flow rate enhances with the amplitude of the channel walls for Pe Cri ≤ Pe ≤323.5. Moreover, for Δϕ = 0, the value of mixing efficiency increases with α for 786 ≤ Pe ≤1000 with a 9.17% decrement in the flow rate for the change in α from 0.05 to 0.25.

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Electroosmotic flow of a Phan-Thien–Tanner fluid in a wavy-wall microchannel

Cited by 35 publications

References 20 publications

Mathematical study of viscoelastic polymer during roll-over-web coating

Mathematical study of viscoelastic polymer during roll-over-web coating

Analogue tuning of particle focusing in elasto-inertial flow

Enhanced Electroosmotic Mixing in a Wavy Micromixer Using Surface Charge Heterogeneity

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