A model for the prediction of onset of flooding in PEM fuel cells

An isothermal, quasi-two-dimensional model is presented, which enables the prediction of when two-phase flow and flooding may occur in a typical polymer electrolyte membrane (PEM) fuel cell stack. The model solves, at a given section of the membrane-electrode assembly (MEA), for the local current density and water vapor concentration in the anode and the cathode electrodes and in the gas channels by solving the Stefan-Maxwell equations for multi-component diffusion in the MEA. Two-phase flow, which would eventually lead to flooding, is expected to occur when the relative humidity approaches 100% on the anode or the cathode side. The model involves a system of non-linear algebraic equations, which has been solved using the optimization toolbox in MATLAB. The experimental results of Tuber et al., who reported on the visual observations of two-phase flow in a PEM fuel cell, are used to validate the model. This is an abstract of a paper presented at the 7th World Congress of Chemical Engineering (Glasgow, Scotland 7/10-14/2005).