A Study on the CFD-guided Gas Flow Field Plate Optimization of a PEM Fuel Cell with Wave Flow Channels

The gas flow field design of proton exchange membrane (PEM) fuel cells is crucial to achieve high and stable performance. Since the mass transfer process of air is much more difficult than that of hydrogen, and the possible occurrence of flooding could make performance deteriorate rapidly, the gas flow in the cathode plate is especially important. In the present study, three-dimensional (3D) computational fluid dynamics (CFD) simulations were conducted to evaluate and optimize the performance of a baseline flow field pattern, which is characterized by wave flow channels. The active area is up to the same order as that of commercial products. To consider the turbulent flow, the Reynolds-averaged Navier-Stokes (RANS) approach coupled with the standard k-ω model was used. Moreover, a blend of the viscous and log-law solutions was implemented to calculate the specific dissipation rate in grids near the wall. A flexible grid control method, adaptive mesh refinement (AMR), consisting of both boundary AMR and sub-grid scale (SGS) AMR was also adopted to accelerate simulations while maintaining good accuracy. To validate numerical models, the total pressure losses which were calculated from simulations and obtained from measured data under different boundary conditions have been compared. Results showed that simulations matched well with experimental data. Furthermore, the effect of flow field changes in distribution and reaction zones on both the flow uniformity and pressure loss was investigated. Finally, a methodology to quickly estimate the pressure losses with different channel depths was demonstrated. The correlation analysis results showed that the overall pressure drop has an obvious linear correlation with the inverse square of channel depth.