Numerical Investigation of Cross Flow on the Performance of Polymer Electrolyte Fuel Cell

Abstract

A three dimensional, single-phase, isothermal study of a polymer electrolyte fuel cell (PEFC) was conducted to investigate the mechanism of convective flow effect on the performance of fuel cell. Convective flow was caused by inlet velocity and cross flow through the GDL. To clarify the mechanism of cross flow effect on the performance of PEFC, it was induced in the parallel flow field, whereas cross flow inherently appear in the serpentine flow fields. In addition, to isolate the contribution of cross flow on the performance, the simulation was executed with a low current density where oxygen transport resistance was stronger than proton/electron transport resistance. Gas channels with a smaller pitch length produced a more uniform current density than those with a larger pitch length. With increase of inlet velocity the performance increases for any values of pitch length. Cross flow through the GDL caused by the differential pressure between adjacent channels had significantly enhanced the local current density of a PEFC and simultaneously increased the degree of non-uniformity in the current density. The cross flow can increase the performance of fuel cell by reducing the oxygen transport resistance. Therefore, it is possible to overcome the oxygen transport limitation by inducing cross flow.