Fluid Transport Mechanisms in Microfluidic Devices

Molho, Joshua I.; Herr, Amy E.; Kenny, Thomas W.; Mungal, M. G.; Deshpande, Manish; Gilbert, John R.; Garguilo, Michael G.; Paul, Phillip H.; John, Pamela M. St.; Woudenberg, Timothy M.; Connell, Charles R.

doi:10.1115/imece1998-1224

Cited by 12 publications

(11 citation statements)

References 5 publications

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“…As the field strength increases above E ~ 100 V /cm, the parabolic profile becomes more pronounced. The increasing parabolic profile with increasing field strength has also been observed in straight microchannels (data not shown) and straight capillaries [10] and is therefore not due to the asymmetry in the field. The simulations in this field range di(j not match the experimental data.…”

Section: Figure 6 Graph Of the Simulated Band Width At Two Distinct T...supporting

confidence: 66%

Metrology and Simulation of Chemical Transport in Microchannels

John¹,

Woudenberg²,

Connell³

et al. 1998

1998 Solid-State, Actuators, and Microsystems Workshop Technical Digest

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We are working towards building a CAD tool (NetFlow) for microfluidic systems. To support the development of this tool, diffusion and flow experiments are being performed in microchannels. In this paper, we describe the novel flow visualization approach developed for these experiments and report experimental results and corresponding simulations for fluid transport in microchannels. The experimental approach relies on the use of a caged, charged fluorescent dye which can be activated (uncaged) by a UV laser beam and tracked by fluorescence imaging (1). In contrast to standard methods for inserting a dye plug in a microchannel, this is the only technique which allows definition of very precise regions at any place along the channel. Specifically, this allows a narrow definition of starting plugs and therefore an improved determination of the flow profile. We have used this technique to study diffusion, pressure-driven flow, and electrokinetic flow in various microchannel geometries.

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Section: Figure 6 Graph Of the Simulated Band Width At Two Distinct T...supporting

confidence: 66%

Metrology and Simulation of Chemical Transport in Microchannels

John¹,

Woudenberg²,

Connell³

et al. 1998

1998 Solid-State, Actuators, and Microsystems Workshop Technical Digest

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“…Based on the study of Probstein (2005), electrokinetic effects were initially described by Reuss (1809) in 1809, followed by fundamental studies of Von Helmholtz (1879) on EDL theory that relied on electrical and flow parameters for electrokinetic transport (Probstein, 2005). Regarding experimental studies and numerical simulation, Molho et al (1998) presented results for electrokinetic flows in microchannels, focusing on microfluidic applications, according to which Joule thermal effects and changes associated with the viscosity of fluid were demonstrated as secondary effects and compared with the pressure gradient of cocurrent flow. On the other hand, the analytical and experimental solution is an attractive field of study whose outcomes are most accurate and reliable (Norouzi et al, 2019a(Norouzi et al, , 2019b(Norouzi et al, , 2021Emamian et al, 2021;Norouzi et al, 2019aNorouzi et al, , 2019b.…”

Section: Carreau-yasuda Modelmentioning

confidence: 99%

Numerical simulation of the electroosmotic flow of the Carreau-Yasuda model in the rectangular microchannel

Ghorbani

Emamian

Ellahi

et al. 2021

HFF

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Purpose In this paper aims to investigate the numerical simulation of the electroosmotic flow of the Carreau-Yasuda model in the rectangular microchannel. Electromagnetic current is generated by applying an effective electric field in the direction of the current. Design/methodology/approach The non-Newtonian model used is the five-constant Carreau-Yasuda model which the non-Newtonian properties of the fluid can be well modeled. Using the finite difference method, the potential values at all points in the domain are obtained. Then, the governing equations (momentum conservation) and the energy equation are segregated and solved using a finite difference method. Findings In this paper, the effect of various parameters such as Weisenberg number, electrokinetic diameter, exponential power number on the velocity field and Brinkman and Pecklet dimensionless numbers on temperature distribution are investigated. The results show that increasing the Weissenberg dimensionless number and exponential power and diameter parameters reduces the maximum velocity field in the microchannel. Originality/value To the best of the authors’ knowledge, this study is reported for the first time.

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“…The electroosmotic potential, in the limit of small yet finite Debye layers, loses strength very fast within the thin EDL and a uniform "plug like" velocity profile can be observed in most of the channel [6]. The plug flow behavior has been found in various experiments [21,22,23]. The fluid in a capillary travels like plug flow under the action of electroosmotic force as the velocity at the solid surface can be considered to be nonslip and the driving force for fluid movement is acting only within the thin electric double layer.…”

Section: Introductionmentioning

confidence: 82%

Electroosmotic flow of a rheological fluid in non-uniform micro-vessels

2022

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The paper deals with a theoretical study of electrokinetic flow of a rheological Herschel-Bulkley fluid through a cylindrical tube of variable cross-section. The concern of this study is to analyze combined pressure-driven and electroosmotic flow of Herschel-Bulkley fluid.The wall potential is considered to vary slowly and periodically along the axis of the tube.With reference to flow in the micro-vessels, the problem has been solved using the lubrication theory. The Helmholtz-Smoluchowski (HS) slip boundary condition has been employed in this study. Volumetric flow rate Q is found to be significantly affected by the yield stress parameter ν only if an applied pressure force is active. The linear superposition of flow components separately due to the hydrodynamic and electric force occurs only for a strictly uniform tube. This linear relationship fails if non-uniformity appears in either tube radius or in distribution of the electrokinetic slip boundary condition. Moreover, converging/diverging nature of the mean tube radius plays a crucial role on the fluid transport. For the benefit of readers, along with the original contribution, some applications of external electrical stimulation (ES) in the human body and HS slip velocity, studied in the

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Fluid Transport Mechanisms in Microfluidic Devices

Cited by 12 publications

References 5 publications

Metrology and Simulation of Chemical Transport in Microchannels

Metrology and Simulation of Chemical Transport in Microchannels

Numerical simulation of the electroosmotic flow of the Carreau-Yasuda model in the rectangular microchannel

Electroosmotic flow of a rheological fluid in non-uniform micro-vessels

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