Modeling non-isothermal two-phase multicomponent flow in the cathode of PEM fuel cells

A two-dimensional, non-isothermal, two-phase, multicomponent model is presented for the cathode of a PEM fuel cell, which can be applied using both conventional and interdigitated gas distributors. Gas and liquid transport are described by an extended Darcy’s law using a continuum approach. The most important material properties like wettability, permeability, porosity and tortuosity are determined experimentally. For the determination of the capillary pressure–saturation data, a method based on mercury intrusion porosimetry has been applied. The relative permeability was then derived from this data. It turned out however, that a more detailed description of the partial wetting behaviour of hydrophobic electrodes is of decisive importance. The two-dimensional distribution of the reactants and products is obtained and depends strongly on the flow configuration and the operational conditions. The model results were compared to experimental data and qualitative information on the effects of various operating conditions and on material properties were obtained.