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dc.contributor.authorGarcia-Salaberri, Pablo A.
dc.contributor.authorGostick, Jeff T.
dc.contributor.authorHwang, Gisuk
dc.contributor.authorWeber, Adam Z.
dc.contributor.authorVera, Marcos
dc.identifier.citationGarcia-Salaberri, Pablo A.; Gostick, Jeff T.; Hwang, Gisuk; Weber, Adam Z.; Vera, Marcos. 2015. Effective diffusivity in partially-saturated carbon-fiber gas diffusion layers: effect of local saturation and application to macroscopic continuum models. Journal of Power Sources, vol. 296, 20 November 2015:pp 440–453en_US
dc.descriptionClick on the DOI link to access the article may not be fee).en_US
dc.description.abstractMacroscopic continuum models are an essential tool to understand the complex transport phenomena that take place in gas diffusion layers (GDLs) used in polymer electrolyte fuel cells (PEFCs). Previous work has shown that macroscopic models require effective properties obtained under uniform saturation conditions to get a consistent physical formulation. This issue, mostly unappreciated in the open literature, is addressed in detail in this work. To this end, lattice Boltzmann simulations were performed on tomographic images of dry and water-invaded carbon-paper GDL subsamples with nearly uniform porosity and saturation distributions. The computed effective diffusivity shows an anisotropic dependence on local porosity similar to that reported for morphologically analogous GDLs. In contrast, the dependence on local saturation is rather isotropic, following a nearly quadratic power law. The capability of the local correlations to recover the layer-scale properties obtained from inhomogeneous GDLs is checked by global averaging. Good agreement is found between the upscaled results and the diffusivity data of the GDL from which the present subsamples were taken, as well as other global data presented in the literature. A higher blockage effect of local saturation is, however, expected for the under-the-rib region in operating PEFCs.en_US
dc.description.sponsorshipThe authors thank Dr. Jin Hyun Nam (Daegu University, South Korea), Dr. Massoud Kaviany (University of Michigan, USA) and Dr. Felix N. Buchi (Paul Scherrer Institut, Switzerland) for insightful discussions and comments concerning their works. The authors also thank Dr. Dula Parkinson and Dr. Alastair MacDowell at the Advanced Light Source (ALS) for help in obtaining the tomographic images, as well as the support team of Calcul Quebec and Compute Canada for their help during the simulation campaign. This work was supported by the Natural Science and Engineering Research Council of Canada's Discovery Grant program, the Assistant Secretary for Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U. S. Department of Energy under contract DE-AC02-05CH11231, and Project ENE2011-24574 of the Spanish Ministerio de Economia y Competitividad (MEC). XCT experiments were performed on beamline 8.3.2 at the ALS, Lawrence Berkeley National Laboratory, which is a national user facility funded by the Department of Energy, Office of Basic Energy Sciences under contract DE-AC02-05CH11231. Numerical calculations were conducted on the supercomputing clusters Guillimin and Colosse managed by Calcul Quebec and Compute Canada. The operation of these supercomputers is funded by the Canada Foundation for Innovation (CFI), Ministere de l'Economie, de l'Innovation et des Exportations du Quebec (MEIE), RMGA and the Fonds de recherche du Quebec - Nature et technologies (FRQ-NT). Natural Science and Engineering Research Council of Canada's Discovery Grant programen_US
dc.publisherElsevier B.V.en_US
dc.relation.ispartofseriesJournal of Power Sources;v.296
dc.subjectGas diffusion layeren_US
dc.subjectMacroscopic continuum modelingen_US
dc.subjectEffective diffusivityen_US
dc.subjectWater saturationen_US
dc.subjectX-ray tomographyen_US
dc.subjectLattice Boltzmann methoden_US
dc.titleEffective diffusivity in partially-saturated carbon-fiber gas diffusion layers: effect of local saturation and application to macroscopic continuum modelsen_US
dc.rights.holderCopyright © 2015 Elsevier B.V. Published by Elsevier B.V. All rights reserved.en_US

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