CFD analysis of a constructal flow distributor as a bipolar plate for PEMFCs

A plate-type constructal flow distributor is implemented as a gas distributor for a proton exchange membrane fuel cell. A 3D complete model is simulated using CFD techniques. The fuel cell model includes the gas flow channels, the gas diffusion layers and the membrane electrode assembly (MEA). The governing equations for the mass and momentum transfer are solved including the pertinent source terms due to the electrochemical reactions in the different zones of the fuel cell. Similar configurations have been already presented in previous studies but using the flow distributor as a heat remover; however, the similarity between heat transfer and mass transfer phenomena has lead to investigate the performance of such distributors in fuel cells. In terms of flow analysis, it was found that the constructal flow distributor presents a low pressure drop for a wide range of Reynolds number conditions at the inlet, as well as an excellent uniformity of flow distribution. Some of the advantages of the constructal model, over traditional flow patterns, are the uniformity of current density distribution, the adequate consumption of species and the possibility to increase the bifurcation levels to cover a larger reaction area.