Gas Transport Properties in Gas Diffusion Layers: A Lattice Boltzmann Study

Munekata, Toshihisa; Inamuro, Takaji; Hyodo, Shi‐aki

doi:10.4208/cicp.301009.161210s

Cited by 5 publications

(4 citation statements)

References 12 publications

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“…Therefore, more sophisticated models focusing only on the water transport in the GDL domain and its implications on gas transport have been developed, based either on pore network modeling, 26,27 two-phase Lattice Boltzmann models, 14,[27][28][29] or other approaches. 30,31 These models incorporate the complex geometry of the GDL on the pore scale (from X-ray micro-tomography or artificial reconstructions), but their validity is unclear due to assumptions needed e.g.…”

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confidence: 99%

“…In PEFC multi-physics modeling, water transport in the GDL is typically included based on a macro-homogeneous description, [16][17][18][19][20][21][22][23][24][25] which so far could not properly describe the effects of two-phase water transport and the related influences on mass transport and fuel cell performance. Therefore, more sophisticated models focusing only on the water transport in the GDL domain and its implications on gas transport have been developed, based either on pore network modeling, 26,27 two-phase Lattice Boltzmann models, 14,[27][28][29] or other approaches. 30,31 These models incorporate the complex geometry of the GDL on the pore scale (from X-ray micro-tomography or artificial reconstructions), but their validity is unclear due to assumptions needed e.g.…”

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confidence: 99%

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Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Rosén

Eller²,

Kang

et al. 2012

J. Electrochem. Soc.

127

122

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Operating Polymer Electrolyte Fuel Cells (PEFC) under high current density conditions, causes significant losses related to liquid water saturation in the gas diffusion layer (GDL). The blockage of pores inside the material has a strong influence on its effective gas transport properties. Here we report on the combination of in-situ X-ray tomographic microscopy (XTM) of PEFC and the numerical determination of gas transport properties using Lattice Boltzmann and finite difference methods. The GDL domains (Toray TGP-H-060) of two identical cells, each with 11 mm 2 active area, were analyzed in sections of about 0.3 to 0.8 mm 2 size. Saturation levels between 0.1 and 0.4 were found, with higher saturation under the ribs. The saturated and the non-saturated states of the GDL samples were compared in order to quantify the dependence of gas phase permeability and effective relative diffusivity on liquid water saturation. Both these relative measures were found to follow power relationships of (1 − s) λ , where the exponent λ was approximately 3 for all cases except for the in-plane diffusivity where it was closer to 2.Performance of polymer electrolyte fuel cells (PEFC) at high current densities is limited by mass transport losses associated with the presence of liquid water in the porous structures. In the gas diffusion layers (GDL) this issue is particularly relevant.The porous GDL structure allows collecting current under the flow field channels and provides access for the gases under the ribs. 1 This requires a high permeability and relative diffusivity in the pore space and a high conductivity in the solid. GDLs, made from carbon fibers with diameters in the order of typically 6-8 μm, have porosities around 75% and the internal surface is treated with hydrophobing agents. The formation and transport of liquid water in the GDL is thus governed by its internal structure and surface properties, and the presence of liquid water in the pore space of the GDL influences its gas transport properties. At high current density and/or moderate temperature conditions, the oxygen transport in the cathode GDL is particularly affected, which may lead to significant overvoltages. 2,3The effective relative diffusivity of GDLs has been determined with sulphuric acid filled samples and an electrochemical method. 4,5 LaManna et al. 6 have obtained the effective relative diffusivity in a test cell by inducing mass transfer using a concentration gradient of water vapor. These methods however fail to produce saturation dependent results. Opposite to the experimental methods, effective medium theory was used to describe the diffusion through a porous medium consisting of packed spheres. 7 Later, numerical models yielded similar relations particularly for hydrophobic fibrous materials such as the GDL. Tomadakis and Sotirchos 8 used Monte-Carlo simulations in fiber structures and found that the effective relative diffusivity was strongly dependent on the fiber orientation. Nam and Kaviany 9 extended the work of Tomadakis and Sotirchos 8 and...

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confidence: 99%

mentioning

confidence: 99%

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Rosén

Eller²,

Kang

et al. 2012

J. Electrochem. Soc.

127

122

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“…The transport properties of the material can change due to compression [2], or due to the presence of water under normal operating conditions of the fuel cell [3]. The use of computational methods along with structures obtained via X-ray tomographic microscopy (XTM), can provide the insight needed to optimize the design and the working efficiency of such devices [4][5][6][7]. Using a flow solver, apart from optimizing the flux of reactants to the MEA, it can also determine if water accumulation can be correlated to high/low velocity regions of the GDL (or other flow properties).…”

Section: Introductionmentioning

confidence: 99%

Simulation of 3D Porous Media Flows with Application to Polymer Electrolyte Fuel Cells

Prasianakis

Rosén

Kang

et al. 2013

Commun. comput. phys.

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A 3D lattice Boltzmann (LB) model with twenty-seven discrete velocities is presented and used for the simulation of three-dimensional porous media flows. Its accuracy in combination with the half-way bounce back boundary condition is assessed. Characteristic properties of the gas diffusion layers that are used in polymer electrolyte fuel cells can be determined with this model. Simulation in samples that have been obtained via X-ray tomographic microscopy, allows to estimate the values of permeability and relative effective diffusivity. Furthermore, the computational LB results are compared with the results of other numerical tools, as well as with experimental values.

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“…Gas transport in porous media has gained much attention owing to its wide applications, such as optimizing the performance of fuel cells [1] , enhancing the efficiency of catalytic reactions [2] , and developing methane gas from unconventional reservoirs (e.g., shale gas [3] and coalbed methane [4] ). Gas transport is a generalized concept that can be classified into viscous flow driven by a pressure gradient, and mass diffusion driven by a concentration gradient.…”

Section: Introductionmentioning

confidence: 99%

Identifying the dominant transport mechanism in single nanoscale pores and 3D nanoporous media

Yin

Prodanović

et al. 2023

Fundamental Research

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Gas Transport Properties in Gas Diffusion Layers: A Lattice Boltzmann Study

Cited by 5 publications

References 12 publications

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Simulation of 3D Porous Media Flows with Application to Polymer Electrolyte Fuel Cells

Identifying the dominant transport mechanism in single nanoscale pores and 3D nanoporous media

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