Autonomous filling of a viscoelastic fluid in a microfluidic channel: Effect of streaming potential

Gaikwad, Harshad Sanjay; Roy, Arun K.; Mondal, Pranab Kumar

doi:10.1016/j.jnnfm.2020.104317

Cited by 18 publications

(3 citation statements)

References 38 publications

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“…Similarly, combined electro-osmotic and pressure-driven flows in viscoelastic mediums have also been analysed [31,[36][37][38] to explore the possibilities of finetuning flow rates in narrow channels. EDLs are also associated with generation of streaming potential [39], defined as the electric field induced because of the flow actuated typically by a pressure/mechanical gradient; a number of studies [40][41][42][43] on the streaming potential in viscoelastic and other non-Newtonian mediums have been carried out in recent years with potential applications in energy conversion in miniaturized devices.…”

Section: Introductionmentioning

confidence: 99%

Combined electromechanically driven pulsating flow of nonlinear viscoelastic fluids in narrow confinements

Kumar

Mukherjee

Sinha

et al. 2022

J. R. Soc. Interface.

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Controlled microscale transport is at the core of many scientific and technological advancements, including medical diagnostics, separation of biomolecules, etc., and often involves complex fluids. One of the challenges in this regard is to actuate flows at small scales in an energy efficient manner, given the strong viscous forces opposing fluid motion. We try to address this issue here by probing a combined time-periodic pressure and electrokinetically driven flow of a viscoelastic fluid obeying the simplified linear Phan-Thien–Tanner model, using numerical as well as asymptotic tools, in view of the fact that oscillatory fields are less energy intensive. We establish that the interplay between oscillatory electrical and mechanical forces can lead to complex temporal mass flow rate variations with short-term bursts and peaks in the flow rate. We further demonstrate that an oscillatory pressure gradient or an electric field, in tandem with another steady actuating force can indeed change the net throughput significantly—a paradigm that is not realized in Newtonian or other simpler polymeric liquids. Our results reveal that the extent of augmentation in the flow rate strongly depends on the frequency of the imposed actuating forces along with their waveforms. We also evaluate the streaming potential resulting from an oscillatory pressure-driven flow and illustrate that akin to the volume throughput, the streaming potential also shows complex temporal variations, while its time average gets augmented in the presence of a time-periodic pressure gradient in a nonlinear viscoelastic medium.

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Section: Introductionmentioning

confidence: 99%

Combined electromechanically driven pulsating flow of nonlinear viscoelastic fluids in narrow confinements

Kumar

Mukherjee

Sinha

et al. 2022

J. R. Soc. Interface.

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“…Underlying physical issues involved with the transportation of a very small volume in miniaturized devices/systems are fundamentally important in different areas of microfluidics. The paradigm demands a thorough understanding of the capillary filling phenomenon [1][2][3][4][5][6][7][8]. In microfluidic confinement, a small volume of liquid moves upon experiencing the thermodynamic force (capillary force), which is the culmination of the minimization of the interfacial free energy of the system (fluid-fluid-solid).…”

Section: Introductionmentioning

confidence: 99%

Capillary imbibition of non-Newtonian fluids in a microfluidic channel: analysis and experiments

et al. 2020

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We have presented an experimental analysis on the investigations of capillary filling dynamics of inelastic non-Newtonian fluids in the regime of surface tension dominated flows. We use the Ostwald–de Waele power-law model to describe the rheology of the non-Newtonian fluids. Our analysis primarily focuses on the experimental observations and revisits the theoretical understanding of the capillary dynamics from the perspective of filling kinematics at the interfacial scale. Notably, theoretical predictions of the filling length into the capillary largely endorse our experimental results. We study the effects of the shear-thinning nature of the fluid on the underlying filling phenomenon in the capillary-driven regime through a quantitative analysis. We further show that the dynamics of contact line motion in this regime plays an essential role in advancing the fluid front in the capillary. Our experimental results on the filling in a horizontal capillary re-establish the applicability of the Washburn analysis in predicting the filling characteristics of non-Newtonian fluids in a vertical capillary during early stage of filling (Digilov 2008 Langmuir 24 , 13 663–13 667 ( doi:10.1021/la801807j )). Finally, through a scaling analysis, we suggest that the late stage of filling by the shear-thinning fluids closely follows the variation x ~ t . Such a regime can be called the modified Washburn regime (Washburn 1921 Phys. Rev. 17 , 273–283 ( doi:10.1103/PhysRev.17.273 )).

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“…In most of the applications, as mentioned above, the working fluid exhibits non-Newtonian rheological behaviour. The momentum equations governing the flow dynamics of non-Newtonian fluids are, however, contain the non-linear diffusion terms [18][19][20][21][22][23][24] . Existence of the non-linear diffusion terms in the momentum equations makes these equations analytically intractable essentially for obtaining the desired solutions 15,18,25,26 .…”

mentioning

confidence: 99%

Leveraging spreadsheet analysis tool for electrically actuated start-up flow of non-Newtonian fluid in small-scale systems

Roy

Chakraborty

Mondal

2022

Sci Rep

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In this article, we demonstrate the solution methodology of start-up electrokinetic flow of non-Newtonian fluids in a microfluidic channel having square cross-section using Spreadsheet analysis tool. In order to incorporate the rheology of the non-Newtonian fluids, we take into consideration the Ostwald-de Waele power law model. By making a comprehensive discussion on the implementation details of the discretized form of the transport equations in Spreadsheet analysis tool, and establishing the analytical solution for a special case of the start-up flow, we compare the results both during initial transience as well as in case of steady-state scenario. Also, to substantiate the efficacy of the proposed spreadsheet analysis in addressing the detailed flow physics of rheological fluids, we verify the results for several cases with the corresponding numerical results. It is found that the solution obtained from the Spreadsheet analysis is in good agreement with the numerical results—a finding supporting spreadsheet analysis's suitability for capturing the fine details of microscale flows. We strongly believe that our analysis study will open up a new research scope in simulating microscale transport process of non-Newtonian fluids in the framework of cost-effective and non-time consuming manner.

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Autonomous filling of a viscoelastic fluid in a microfluidic channel: Effect of streaming potential

Cited by 18 publications

References 38 publications

Combined electromechanically driven pulsating flow of nonlinear viscoelastic fluids in narrow confinements

Combined electromechanically driven pulsating flow of nonlinear viscoelastic fluids in narrow confinements

Capillary imbibition of non-Newtonian fluids in a microfluidic channel: analysis and experiments

Leveraging spreadsheet analysis tool for electrically actuated start-up flow of non-Newtonian fluid in small-scale systems

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