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

Abstract

In this paper we combine a stochastic 3D microstructure model of a fiber based gas diffusion layer of polymer electrolyte fuel cells with a Lattice Boltzmann model for fluid transport. We focus on a simple approach of compressing the planar oriented virtual geometry of paper-type gas diffusion layer from Toray. Material parameters -permeability and tortuosity -are calculated from simulation of one phase, one component gas flow in stochastic geometries. We analyze the statistical spread of simulation results on ensembles of the virtual geometry, both uncompressed and compressed. The influence of the compression is discussed with regard to the Kozeny-Carman equation. The effective transport properties calculated from transport simulations in compressed gas diffusion layers agree well with a trend based on the Kozeny-Carman equation.

Virtual Liquid Water Intrusion in Fuel Cell Gas Diffusion Media

“…Therefore, it is also critical to assess the errors on transport property predictions associated with inaccuracies during the water intrusion process. Gas transport in the GDL microstructures has been simulated using PNM, 36,37,63,64 LBM 10,21,30,45,[65][66][67][68][69] and porescale CFD simulations, 23,[25][26][27]70,71 however the obtained results are seldom compared to experimental observation and the sensitivity of transport property predictions to errors in water distribution have not been discussed.…”

Effective gas diffusion coefficient in fibrous materials by mesoscopic modeling

“…The single component gas flow and effective permeability in fibrous materials has been widely studied usually by combining stochastic method for structure generation and highly efficiency numerical schemes like the lattice Boltzmann method [18,19]. In contrast, there is much less work on the gas diffusion in fibrous structures as another important mass transport process.…”

Quantitative relationships between microstructure and effective transport properties based on virtual materials testing

“…An alternative approach to test the formulas for a micro–macro relationship is based on the application of microscale transport models (micromodels), which are suitable to study microstructure effects. For this purpose, Lattice Boltzmann modeling (LBM) or finite element modeling (FEM), respectively, can be used to solve transport equations based on a structural grid. This grid, which represents the three‐dimensional (3‐D) morphological details of the microstructure, can be obtained by transformation of 3‐D‐data from high‐resolution tomography .…”