(538c) 3-D Modeling of a Proton Exchange Membrane Fuel Cell with Anisotropic Material Properties

Fuel cell performance is dependent on a strongly coupled interaction taking place between convection, diffusion, electrochemical reactions, membrane water transport and heat transfer. Furthermore, the thermal and electrical properties of materials used in fuel cells are anisotropic. In addition, during normal operation of the fuel cell, the two phases of water are present both in the porous gas diffusion layers and in the channels of the oxidant and the fuel. To properly model the effect of all these phenomena in three dimensions with all the couplings and the anisotropy of the material properties presents a significant challenge. In this paper, aspects of a CFD-based modelling approach will be presented. Such an approach takes into account the coupling of the above phenomena by making some engineering assumptions in handling of the individual phenomenon. It is also able to treat the material anisotropy and different material properties used in the fuel cell and thus can be used as an engineering tool for understanding the impact of material changes in future designs. Typical results from these coupled 3-D simulations, which account for the anisotropic material properties, are presented. It is concluded that anisotropic properties play an important role in the coupled transport in a PEMFC and thus accurate measurement of these material properties for input in computational models is needed.