Experimental and pore-level numerical investigation of water evaporation in gas diffusion layers of polymer electrolyte fuel cells

Safi, Mohammad Amin; Prasianakis, Nikolaos I.; Mantzaras, John; Lamibrac, Adrien; Büchi, Félix N.

doi:10.1016/j.ijheatmasstransfer.2017.07.050

Cited by 46 publications

(43 citation statements)

References 51 publications

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“…Results of the simulation showed good agreement with experimentally obtained wet GDL datasets, highlighting that the model constructed was efficient at predicting liquid water saturation in the GDL [131]. Other demonstrations of imagebase modelling have included a number of studies using X-ray CT datasets to understand water evaporation in GDLs [132,133].…”

Section: Figurementioning

confidence: 62%

Developments in X-ray tomography characterization for electrochemical devices

et al. 2019

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Over the last century, X-ray imaging instruments and their accompanying tomographic reconstruction algorithms have developed considerably. With improved tomogram quality and resolution, voxel sizes down to tens of nanometres can now be achieved. Moreover, recent advancements in readily accessible lab-based X-ray computed tomography (X-ray CT) instruments have produced spatial resolutions comparable to specialist synchrotron facilities. Electrochemical energy conversion devices, such as fuel cells and batteries, have inherently complex electrode microstructures to achieve competitive power delivery for consideration as replacements for conventional sources. With resolution capabilities spanning tens of microns to tens of nanometres, X-ray CT has become widely employed in the three-dimensional (3D) characterisation of electrochemical materials. The ability to perform multiscale imaging has enabled characterisation from system-down to particle-level, with the ability to resolve critical features within device microstructures. X-ray characterisation presents a favourable alternative to other 3D methods such as focused ion beam scanning electron microscopy, due to its non-destructive nature, which allows four-dimensional (4D) studies, three spatial dimensions plus time, linking structural dynamics to device performance and lifetime. X-ray CT has accelerated research from fundamental understanding of the links between cell structure and performance, to the improvement in manufacturing and scale-up of full electrochemical cells. Furthermore, this has aided in the mitigation of degradation and celllevel failures such as thermal runaway. This review presents recent developments in the use of X-ray CT as a characterisation method and its role in the advancement of electrochemical materials engineering.

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Section: Figurementioning

confidence: 62%

Developments in X-ray tomography characterization for electrochemical devices

et al. 2019

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“…Bei drei Dimensionen erfordern die Grenzflächen zwischen Gebieten unterschiedlicher Größenskalen besondere Aufmerksamkeit. Safi et al simulierten den Wasseraustrag aus einer GDL in einem Versuchsaufbau, der den Luftkanal in einer Brennstoffzelle repräsentiert, mithilfe der Lattice‐Boltzmann‐Methode (LBM). Durch die Auflösung der Mikrostruktur der GDL ist die Simulationsdomäne auf einen kleinen Teil des Luftkanals beschränkt.…”

Section: Introductionunclassified

Statistische Analyse des lokalen Wassertransportes einer Polymer‐Elektrolyt‐Brennstoffzelle

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Reimer

et al. 2019

Chemie Ingenieur Technik

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Der Wassertransport in der Gasdiffusionsschicht (gas diffusion layer, GDL) einer Polymer-Elektrolyt-Brennstoffzelle (PEFC) wurde mithilfe der Lattice-Boltzmann-Methode simuliert. Mit einem stochastischen Geometriemodell wurde ein Ensemble von Mikrostrukturen generiert, die alle stochastisch äquivalent zur realen Struktur einer GDL sind. Die raue Oberfläche der GDL bildet das Interface zwischen GDL und Luftkanal einer PEFC. Die aus der GDL austretenden Wassertropfen wurden hinsichtlich ihrer Kontaktwinkel analysiert und kurz der dynamische Verlauf betrachtet.The water transport in the gas diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC) was simulated using the Lattice Boltzmann method. By means of a stochastic geometry model an ensemble of microstructures was generated, all of them stochastically equivalent to the real structure of a GDL. The rough surface of the GDL defines the interface between the GDL and air channel of a PEFC. The water droplets emerging from the GDL were analyzed statistically regarding their contact angles. A short insight to the dynamics is given.

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“…Such an example is the evolution of a system when simultaneous dissolution and precipitation processes are competing and drive the evolution of the system [11,19]. Efficient parallelization though allows running simulations with many billion degrees of freedom in relatively small computer clusters, especially when GPGPUs are used [20,21]. We note that the numerical extraction of microscopic properties using realistic geometries has the potential to provide useful input to the effective medium theories, which are used to upscale porous medium flows [22] In this paper, we construct pore geometries with target porosity and initial permeability following a methodology similar to [23,24].…”

Section: Introductionmentioning

confidence: 99%

Upscaling Strategies of Porosity-Permeability Correlations in Reacting Environments from Pore-Scale Simulations

et al. 2018

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In geochemically reacting environments, the mineral dissolution and precipitation alters the structural and transport properties of the media of interest. The chemical and structural heterogeneities of the porous media affect the temporal evolution of the permeability with respect to porosity. Such correlations follow a nonlinear trend, which is difficult to estimate a priori and without knowledge of the microstructure itself, especially under the presence of strong chemical gradients. Macroscopic fieldscale codes require such an input, and in the absence of exact descriptions, simplified correlations are used. After highlighting the diversity of microstructural evolution paths, due to dissolution, we discuss possible upscaling strategies.

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Experimental and pore-level numerical investigation of water evaporation in gas diffusion layers of polymer electrolyte fuel cells

Cited by 46 publications

References 51 publications

Developments in X-ray tomography characterization for electrochemical devices

Developments in X-ray tomography characterization for electrochemical devices

Statistische Analyse des lokalen Wassertransportes einer Polymer‐Elektrolyt‐Brennstoffzelle

Upscaling Strategies of Porosity-Permeability Correlations in Reacting Environments from Pore-Scale Simulations

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