Effects of Partially Narrowed Flow Channel on Performance of Polymer Electrolyte Fuel Cell

Partially narrowed flow channel, which is employed in polymer electrolyte fuel cell in second-generation MIRAI aiming at forcing the gas to dive into gas diffusion layer (GDL), is supposed to improve the mass transfer in both in-plane and through-plane directions. In this study, a numerical investigation on varied flow fields have been carried out by CFD techniques via OpenFOAM and verified experimentally. Around 12.6 % of gas dives into the GDL in 4.4 cm 2 flow field with 33 narrowed structures at 500 cm 3 /min flow rate, thus the average oxygen concentration on the catalyst layer surface increases 17.5 %. Furthermore, the Venturi effect in neat-arranged pattern is unbeneficial for the oxygen transfer, while the pressure difference between neighboring channels enhances the mass transfer under the rib in staggered pattern. A promising improvement of the performance of the partially narrowed channels can be expected by optimizing the geometries and the operating conditions.