Dynamical modeling of water transport in polymer electrolyte membrane fuel cell (PEMFC) design

Official URL: http://risc01.sabanciuniv.edu/record=b1143203 (Table of Contents)

A two-dimensional finite element computational fluid dynamics (CFD) model, including coupled partial differential equations of mass, momentum and charge conservation inside a membrane electrode assembly of a polymer electrolyte membrane fuel cell (PEMFC) are developed. The CFD model is solved for PEMFCs with conventional and interdigitated gas flow fields. For the PEMFC with interdigitated flow fields both coflow and counterflow designs are studied. Furthermore a dynamic lumped model based on the formulation of Pukrushpan et al. (2003) is developed with the addition of membrane's transient water transport. Models are validated by comparing the polarization curves with the experimental data of Ticianelli et al. (1988) for MEAs with conventional gas distributors and He et al. (2000) for MEAs with counterflow interdigitated gas distributors. The results of the lumped model and the CFD model for conventional design are shown to be comparable and lumped model proves to be a good substitute of CFD model for control studies. For the interdigitated case, coflow is found to be superior to counterflow in the performance of the cell. Transient and steady-state responses of the fuel cell system to changes in cell voltage, air pressure and relative humidity of air are investigated for each design. The effect of transient water transport is emphasized and it is observed that it plays a critical role in the operation of a PEMFC for both designs.