Investigating the effects of operational factors on PEMFC performance based on CFD simulations using a three-level full-factorial design

This study uses the 3³ full-factorial design, a factorial arrangement with three factors at three-levels, to investigate the main and interaction effects of design parameters on the performance of a single 25 cm² PEMFC cell. The factors considered in this study include the flow channel design, the operational temperature, and the relative humidity of the cathode gas mixture. The gas flow channel patterns for both the anode side and the cathode side are the same as a straight parallel channel design and two modified parallel channel designs. The operational temperatures are selected as 333 K, 343 K, and 353 K. The relative humidity of the cathode gas mixture varies from 50% to 100% at 25% intervals, while the relative humidity of the anode gas mixture remains fixed at 100%. All runs are conducted with a three-dimensional, non-isothermal steady-state fuel cell computational fluid dynamic model (FCFD) with specified boundary conditions. The FCFD model can not only output the polarization curve, but also predict complex multi-physics flow, thermal, mass and ion transport phenomena inside the tiny fuel cell multi-layer structures. This full-factorial design of experimental method reveals that it is possible to not only explore the main effects of this complex multi-physics problem, but also investigate the effects of two-factor interactions for generating maximum power density. Results show that the flow channel design has the most significant effect on the polarization curve; the next is the cell temperature, while the relative humidity of the cathode gas mixture plays only a minor role.