Effective diffusivity and water-saturation distribution in single- and two-layer PEMFC diffusion medium

Nam, Jin Hyun; Kaviany, Massoud

doi:10.1016/s0017-9310(03)00305-3

Cited by 904 publications

(698 citation statements)

References 23 publications

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“…Often, a Bruggeman-type relation is used where n = 1.5; however, recent microscopic simulations and experimental studies have suggested that the value is closer to between 2 and 5 for typical GDLs [5,14,19,20,24,39,40,64]. Although, it should be noted that some of these studies change the volume fraction by compression, which alters the pore network and is different than examining a change in tortuosity and volume fraction due to pore filling.…”

Section: Updated Porous-medium Model and Modeling Methodologymentioning

confidence: 99%

“…In the previous model, a continuous PSD is used along with a two-point discrete contact-angle distribution (CAD). In other words, single hydrophilic and hydrophobic angles are used, which, along with Nam and Kaviany [5], represented the first modeling and concept of mixed or nonhomogeneous wettable pores. In the model described herein, a continuous distribution is used.…”

Section: Updated Porous-medium Model and Modeling Methodologymentioning

confidence: 99%

“…This is typically done by calculating a saturation or liquid pore-volume fraction using relationships such as the Leverett J-function [5][6][7][8][9], and then using the saturation to modify the intrinsic or dry-medium transport properties using relations like those of Corey [10], (Brooks-Corey) [11], Van Genuchten [12], or Bruggemann [13][14][15]. The more intricate porelevel modeling [16][17][18][19][20][21][22][23][24] has allowed the calculation of various transport properties from a handful of statistical structural properties such as pore-and throat-size distributions, porosity, and bulktransport measurements including saturated permeabilities.…”

Section: Introductionmentioning

confidence: 99%

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Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance

Weber¹

2010

Journal of Power Sources

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A macroscopic-modeling methodology to account for the chemical and structural properties of fuel-cell diffusion media is developed. A previous model is updated to include for the first time the use of experimentally measured capillary pressure -saturation relationships through the introduction of a Gaussian contact-angle distribution into the property equations. The updated model is used to simulate various limiting-case scenarios of water and gas transport in fuel-cell diffusion media. Analysis of these results demonstrate that interfacial conditions are more important than bulk transport in these layers, where the associated mass-transfer resistance is the result of higher capillary pressures at the boundaries and the steepness of the capillary pressuresaturation relationship. The model is also used to examine the impact of a microporous layer, showing that it dominates the response of the overall diffusion medium. In addition, its primary mass-transfer-related effect is suggested to be limiting the water-injection sites into the more porous gas-diffusion layer.

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Section: Updated Porous-medium Model and Modeling Methodologymentioning

confidence: 99%

Section: Updated Porous-medium Model and Modeling Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance

Weber¹

2010

Journal of Power Sources

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“…i Nam & Kaviany's Inverted-Tree hypothesis [18] pictures many smaller flows agglomerating into a larger branch towards the gas channel.…”

Section: %mentioning

confidence: 99%

The effects of compression on single and multiphase flow in a model polymer electrolyte membrane fuel cell gas diffusion layer

Tranter

Burns

Ingham

et al. 2015

International Journal of Hydrogen Energy

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A two-dimensional study of an idealised fibrous medium representing the gas diffusion layer of a PEMFC is conducted using computational fluid dynamics. Beginning with an isotropic case the medium is compressed uni-directionally to observe the effects on single and multiphase flow. Relations between the compression ratio and the permeability of the medium are deduced and key parameters dictating the changes in flow are elucidated. The main conclusions are that whilst compression reduces the absolute permeability of an isotropic medium, the creation of anisotropic geometry results in preferential liquid water pathways. The most important parameter for capillary flow, in uniformly hydrophobic media, is the minimum fibre spacing normal to the flow path. The effect is less pronounced with decreasing contact angle and non-existent for neutrally wettable media.

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“…It is well known that microporous layer (MPL) placed between CL and GDL reduces the negative effect of water flooding at cathode (Pasaogullari & Wang, 2004b;Nam & Kaviany, 2003;Nam et al, 2003). MPL consisting of carbon black and PTFE is coated on one side of a coarse GDL, and has micro-structural and highly hydrophobic characteristics.…”

Section: Effect Of Mpl Addition On Water Transport At Cl|gdl Interfacementioning

confidence: 99%

Water Management and Experimental Diagnostics in Polymer Electrolyte Fuel Cell

Nishida¹,

Tsushima²,

Hirai³

2012

Recent Trend in Electrochemical Science and Technology

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Effective diffusivity and water-saturation distribution in single- and two-layer PEMFC diffusion medium

Cited by 904 publications

References 23 publications

Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance

Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance

The effects of compression on single and multiphase flow in a model polymer electrolyte membrane fuel cell gas diffusion layer

Water Management and Experimental Diagnostics in Polymer Electrolyte Fuel Cell

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