An inverse geometry design problem for optimization of single serpentine flow field of PEM fuel cell

The cathode flow-field design of a proton exchange membrane fuel cell (PEMFC) determines its reactant transport rates to the catalyst layer and removal rates of liquid water from the cell. This study optimizes the cathode flow field for a single serpentine PEM fuel cell with 5 channels using the heights of channels 2-5 as search parameters. This work describes an optimization approach that integrates the simplified conjugated-gradient scheme and a three-dimensional, two-phase, non-isothermal fuel cell model. The proposed optimal serpentine design, which is composed of three tapered channels (channels 2-4) and a final diverging channel (channel 5), increases cell output power by 11.9% over that of a cell with straight channels. These tapered channels enhance main channel flow and sub-rib convection, both increasing the local oxygen transport rate and, hence, local electrical current density. A diverging, final channel is preferred, conversely, to minimize reactant leakage to the outlet. The proposed combined approach is effective in optimizing the cathode flow-field design for a single serpentine PEMFC. The role of sub-rib convection on cell performance is demonstrated. © 2010 Professor T. Nejat Veziroglu.