Modeling two-phase flow in PEM fuel cell channels

This paper is concerned with the simultaneous flow of liquid water and gaseous reactants in mini-channels of a proton exchange membrane PEM) fuel cell. Envisaging the mini-channels as structured and ordered porous media, we develop a continuum model of two-phase channel ow based on two-phase Darcy’s law and the M2 formalism, which allow estimate of the parameters key to fuel cell operation such as overall ressure drop and liquid saturation profiles along the axial flow direction. Analytical solutions of liquid water saturation and species concentrations long the channel are derived to explore the dependences of these physical variables vital to cell performance on operating parameters such as ow stoichiometric ratio and relative humility. The two-phase channel model is further implemented for three-dimensional numerical simulations f two-phase, multi-component transport in a single fuel-cell channel. Three issues critical to optimizing channel design and mitigating channel ooding in PEM fuel cells are fully discussed: liquid water buildup towards the fuel cell outlet, saturation spike in the vicinity of flow cross-sectional eterogeneity, and two-phase pressure drop. Both the two-phase model and analytical solutions presented in this paper may be applicable to more eneral two-phase flow phenomena through miniand micro-channels. 2008 Elsevier B.V. All rights reserved.