Effective transport properties

Abstract

Porous media are an integral part of electrochemical energy conversion and storage devices, including fuel cells, electrolyzers, redox flow batteries and lithium-ion batteries, among others. The calculation of effective transport properties is required for designing more efficient components and for closing the formulation of macroscopic continuum models at the cell/stack level. In this chapter, OpenFOAM is used to determine the effective transport properties of virtually-generated fibrous gas diffusion layers. The analysis focuses on effective properties that rely on the fluid phase, diffusivity and permeability, which are determined by solving Laplace and Navier-Stokes equations at the pore scale, respectively. The model implementation (geometry generation, meshing, solver settings and postprocessing) is described, accompanied by a discussion of the main results. The dependence of orthotropic effective transport properties on porosity is examined and compared with traditional correlations.