Multiscale Modeling of Single-Phase Multicomponent Transport in the Cathode Gas Diffusion Layer of a Polymer Electrolyte Fuel Cell

Abstract

This research reports a feasibility study into multi-scale polymer electrolyte fuel cell (PEFC) modelling through the simulation of macroscopic flow in the multi-layered cell via 1D electrochemical modelling, and the simulation of microscopic flow in the cathode gas diffusion layer (GDL) via 3D single-phase multi-component lattice Boltzmann (SPMC-LB) modelling. The heterogeneous porous geometry of the carbon-paper GDL is digitally reconstructed for the SPMC-LB model using X-ray computer micro-tomography. Boundary conditions at the channel and catalyst layer interfaces for the SPMC-LB simulations such as specie partial pressures and through-plane flow rates are determined using the validated 1D electrochemical model, which is based on the general transport equation (GTE) and volume-averaged structural properties of the GDL. The calculated pressure profiles from the two models are cross-validated to verify the SPMC-LB technique. The simulations reveal a maximum difference of 2.4% between the thickness-averaged pressures calculated by the two techniques, which is attributable to the actual heterogeneity of the porous GDL structure.

3D analysis, modeling and simulation of transport processes in compressed fibrous microstructures, using the Lattice Boltzmann method

“…Ostadi, Rama et al investigated in LB simulations on GDL structures which were obtained from nano-computed tomography. They characterized the structure according to geometric characteristics, anisotropy and effects of compression [41,42,21,43,44,45,46]. As in the macrohomogeneous approaches mentioned before also the simulations on the reconstructed microstructure show the evidence of the non-isotropic transport properties on the behavior of the mass transport on higher spatial scales.…”

“…With this method it is possible to incorporate complex spatial structures in the simulation domain. The features of the method range from single phase, single component flow [16,17] to multi component [18,19,20,21] and/or multi phase configurations [18,22,23,24]. Sophisticated data structures and algorithms can be included [25,26] as well as extended boundary conditions [27,22,28].…”

Simulation of liquid water breakthrough in a nanotomography reconstruction of a carbon paper gas‐diffusion layer

“…The technique applied is fundamentally the same as that applied in the previous work, with the notable exception that different equipment is used here in order to capture the nano-scale porous features as opposed to micro-scale features [10][11][12][13].…”

“…,ಽ ఙ ఋ௫ఙ ಽ [13] where ߪ and ߪ are the water surface tension in the physical domain and the lattice unit, respectively.…”

“…previous work, a 3D LB scheme was progressively developed and applied to examine gas transport through 3D models of the fuel cell GDL which are digitally reconstructed via X-ray nano and micro-tomography. The authors successfully applied the technique to predict gas-phase permeability through uncompressed carbon paper [10], uncompressed carbon cloth [11], compressed carbon cloth [12] and multi-component single-phase transport through carbon paper [13]. The principal difference between these efforts in comparison to the contributions of other studies in the literature is that the authors previous work incorporated 3D models that were generated directly from carbon-based GDLs as manufactured using X-ray tomography, as opposed to employing stochastically-reconstructed models.…”