Numerical study of the effect of the channel and electrode geometry on the performance of microfluidic fuel cells

Khabbazi, Ali Ebrahimi; Richards, Andrew J.; Hoorfar, Mina

doi:10.1016/j.jpowsour.2010.06.094

Cited by 77 publications

(17 citation statements)

References 17 publications

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“…The rates of the electrochemical reactions are assumed to follow Butler-Volmer kinetics equation, which is commonly invoked in fuel cell models. [52][53][54][55][56] Cathode CL.-The rate of formation of CO in the cathode CL depends on the local concentration of CO 2 at the active sites in the CL. As the CL is adjacent to the flowing aqueous electrolyte, it is reasonable to assume the active sites saturated with water and no dependency of water concentration in the rate expression.…”

Section: F25mentioning

confidence: 99%

Modeling and Experimental Validation of Electrochemical Reduction of CO₂to CO in a Microfluidic Cell

Ke-gui

Birgersson

Kim

et al. 2014

J. Electrochem. Soc.

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A steady-state isothermal model is presented for the electrochemical reduction of CO 2 to CO in a microfluidic flow cell. The full cell model integrates the transport of charge, mass, and momentum with electrochemistry for both the cathode and anode. Polarization curves obtained from experiments conducted at different flow rates with varying applied cell potentials are used to determine the kinetic parameters in the electrochemical reaction rate equations. The parameterized model is validated using a different set of experimental results. Good agreement is observed, especially at high cell potentials (-2.5 to -3 V). The model is further used to analyze the effects of several operating parameters, such as applied cell potential, CO 2 concentration of the feed and feed flow rates. The use of the model to analyze the effect of design parameters, such as channel length and porosity of the gas diffusion electrodes, is also demonstrated.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP F28 Journal of The Electrochemical Society, 162 (1) F23-F32 (2015) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP Journal of The Electrochemical Society, 162 (1) F23-F32 (2015) ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IPOn page F28, left column, Figure 2 should beFigure 2. Comparison of polarization curves for (a) parameter fitting and (b) model validation. Feed gas flow rate and compositions are specified inTable 2. Other operating conditions take the base case values in Table 1. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.226.173 Downloaded on 2015-05-18 to IP

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Section: F25mentioning

confidence: 99%

Modeling and Experimental Validation of Electrochemical Reduction of CO₂to CO in a Microfluidic Cell

Ke-gui

Birgersson

Kim

et al. 2014

J. Electrochem. Soc.

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“…In the electrolyte and at the electrodes charge conservation was set. Due to the supporting electrolyte, the electric field in the electrolyte can be described by (Ebrahimi Khabbazi et al 2010…”

Section: Charge Conservationmentioning

confidence: 99%

“…Therefore, the standard exchange current density, where the true value is not known, was adjusted. This value depends on various factors, e.g., on the electrode surface roughness, orientation of the platinum crystals and the CO poisoning of the catalyst (Ebrahimi Khabbazi et al 2010). For j 0,a a value of 1 A m −2 and for j 0,c a value of 0.03 A m −2 was used in the validation study.…”

Section: Validationmentioning

confidence: 99%

“…Therefore the continuous conversion of fuel and oxidant at the electrodes is hindered and result in insufficient power densities and low fuel utilizations. In order to increase the flux through the concentration boundary layer, a decrease in the thickness of the layer is required to create a steep concentration gradient, which leads to high reaction rates at the electrodes and thus to an improved performance of the microfluidic fuel cell (Choban 2004;Ebrahimi Khabbazi et al 2010). A possibility to reduce the size of the concentration boundary layers is to increase the flow rate.…”

Section: Introductionmentioning

confidence: 99%

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Passive control of the concentration boundary layer in microfluidic fuel cells using Dean vortices

Rösing

Schildhauer

König

et al. 2019

Microfluid Nanofluid

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Microfluidic fuel cells are limited by the formation of concentration boundary layers at the electrodes, resulting in low power density and low fuel utilization. This work demonstrates a novel method to enhance the diffusion-limited mass transport by decreasing the size of the concentration boundary layer using Dean vortices. These vortices are induced by a curved microchannel and enhance the mass transport of fresh reactant towards the electrodes. Numerical simulations were performed to show the influence of the Dean vortices on the performance of a microfluidic fuel cell. Furthermore, a curved microfluidic device with segmented electrodes was fabricated, which allows to experimentally investigate the effect of the enhanced diffusion-limited mass transport on the current density of a model redox couple and thus to prove the concept and the numerical results. It is shown that the Dean vortices, evolving in the curved channel, cause a convective transport of fresh solution towards the electrodes yielding a high current density and resulting in an improvement of 30% using a curved microfluidic fuel cell instead of a straight one. On condition that diffusive and convective mass transport are well-balanced, this approach promises not only a higher power density, but also a much higher fuel utilization.

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“…Numerous computational and experimental studies have been performed to find how the performance of LFFCs is affected by the flow rate, concentration, and channel geometry [25][26][27][28][29][30][31]. Tanveer and Kim [16] studied several geometric variations in a LFFC with Y-shaped channel.…”

Section: Introductionmentioning

confidence: 99%

Effects of Bridge-Shaped Microchannel Geometry on the Performance of a Micro Laminar Flow Fuel Cell

Tanveer

Kim

2019

Micromachines

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A laminar flow micro fuel cell comprising of bridge-shaped microchannel is investigated to find out the effects of the cross-section shape of the microchannel on the performance. A parametric study is performed by varying the heights and widths of the channel and bridge shape. Nine different microchannel cross-section shapes are evaluated to find effective microchannel cross-sections by combining three bridge shapes with three channel shapes. A three-dimensional fully coupled numerical model is used to calculate the fuel cell’s performance. Navier-Stokes, convection and diffusion, and Butler-Volmer equations are implemented using the numerical model. A narrow channel with a wide bridge shape shows the best performance among the tested nine cross-sectional shapes, which is increased by about 78% compared to the square channel with the square bridge shape.

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Numerical study of the effect of the channel and electrode geometry on the performance of microfluidic fuel cells

Cited by 77 publications

References 17 publications

Modeling and Experimental Validation of Electrochemical Reduction of CO₂to CO in a Microfluidic Cell

Modeling and Experimental Validation of Electrochemical Reduction of CO₂to CO in a Microfluidic Cell

Passive control of the concentration boundary layer in microfluidic fuel cells using Dean vortices

Effects of Bridge-Shaped Microchannel Geometry on the Performance of a Micro Laminar Flow Fuel Cell

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Numerical study of the effect of the channel and electrode geometry on the performance of microfluidic fuel cells

Cited by 77 publications

References 17 publications

Modeling and Experimental Validation of Electrochemical Reduction of CO2to CO in a Microfluidic Cell

Modeling and Experimental Validation of Electrochemical Reduction of CO2to CO in a Microfluidic Cell

Passive control of the concentration boundary layer in microfluidic fuel cells using Dean vortices

Effects of Bridge-Shaped Microchannel Geometry on the Performance of a Micro Laminar Flow Fuel Cell

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Modeling and Experimental Validation of Electrochemical Reduction of CO₂to CO in a Microfluidic Cell

Modeling and Experimental Validation of Electrochemical Reduction of CO₂to CO in a Microfluidic Cell