Two-dimensional simulation of water transport in polymer electrolyte fuel cells

A two-dimensional finite-element-based model of coupled fluid flow, mass tr ansport, and electrochemistry is derived for a polymer electrolyte fuel cel l operating without external humidification of the reactant gases. Transpor t in the gas channels and gas-diffusion electrodes is modeled using the con tinuity, potential flow, and Stefan-Maxwell equations. Concentrated solutio n theory is used to model transport within the membrane. Predictions of the fraction of product water leaving the anode side of the fuel cell are comp ared to recent experimental studies in the literature. The present model co rrectly predicts the dependence of product water leaving the anode on hydro gen stoichiometry, oxygen stoichiometry, current density, and cell temperat ure. The multidimensional nature of transport within such a fuel cell is di scussed and plots of streamlines, gas mole fractions, and water content of the membrane are presented. (C) 2000 Elsevier Science Ltd. All rights reser ved.