Flow maldistribution in interdigitated channels used in PEM fuel cells

The interdigitated flow configuration is unique in the sense that the reactants are forced through the porous electrodes in this configuration, whereas this occurs by diffusion in the conventional types of flow fields. Previous studies have shown that this reduces the possibility of flooding of the cathode electrode resulting in improved efficiency of the fuel cell, however, at the cost of a higher-pressure drop. In the present study, computational fluid dynamics (CFD)-based simulations have been used to study the effect of important geometric parameters such as the channel, the header and the electrode dimensions. The results show that for low permeabilities the flow is uniform across the porous electrode; however, for permeabilities in the range of 10−11 to 10−10 m2, the flow may become non-uniform. Under these conditions, calculations in four-cell and eight-cell parallel interdigitated configuration show that significant flow maldistribution among the parallel channels is likely to occur.