Generalization of a CFD Model to Predict the Net Power in PEM Fuel Cells

Abstract

Qualitatively, it is known that the reactants content within the catalyst layer (CL) is the driving moments for the kinetics of reaction within the CL. This paper aimed to quantitatively express the level of enhancement in electrical power due to enrichment in the oxygen content. For a given MEA, a flow field (FF) designer is always willing to design a FF to maximize the content of oxygen in all regions of the CL. Using the guidelines provided in this paper, FF-designers can predict the enhancement in electrical power achieved due to 1% enrichment in oxygen content within the CL without cumbrous CFD computations. A three dimensional CFD tool has been used to answer to this question. It simulates a steady, single-phase flow of the reactant-product, a moist air mixture, in the air side electrode of a proton exchange membrane fuel cell (PEMFC). The task was performed for different channel geometries, all parallel straight flow fields (FF), and a relationship between the oxygen content at the face of the CL and the cell net power was developed. It is observed that at V=0.35 V, for 1% enrichment in oxygen content within the CL, the net power was enhanced by 3.5%.