Numerical investigation on the effect of hydrothermal behavior of flow dynamics for PEM fuel cell

• Provision of a (CFD) model that effectively simulates the complex interactions within PEM fuel cells. • Provides an in-depth examination of the hydrothermal stresses affecting PEMs. • Identifies specific degradation mechanisms related to operational conditions • Better design practices and material selection, ultimately enhancing the reliability and efficiency of fuel cell technologies. • The effectiveness and longevity of PEM fuel cells are significantly impacted. This study analyzes the performance and heat management of proton exchange membrane fuel cells (PEMFCs) based on a computational approach. It derives a three-dimensional steady-state incompressible flow model coupled with mass, momentum, energy, and species transport in the PEMFC. The model incorporates forced convection in reactant flow channels and cooling circuits and the volume of fluid (VOF) technique for two-phase flow behavior description. The optimization of some primary operating parameters, like temperature, relative humidity, and stoichiometry, is emphasized to ensure optimum water management and thermal efficiency in the study. Numerical verification is performed with a well-defined PEMFC with serpentine flow fields, and the numerical predictions are found to have a good correlation with the results, with the highest deviation being 5% in voltage and 3% in temperature distribution. The findings indicate that the best operating temperature range of 333.15 to 353.15 K (60 to 80°C) and relative humidity (RH) of 60 to 70% significantly improve the performance of cells, with an optimal power output of 1.2 Wcm - ² and electrical efficiency of 60%. The pressure loss in the cathode channel is 200 Pa, and the water removal efficiency is 85% under these operating conditions. Besides, operating with a 1.5 to 2.0 stoichiometric flow ratio for anode and cathode reactants continues to offer enhanced performance and doubles the power production of lower stoichiometric ratios by 20%. The study further indicates the importance of flow field design to alleviate flooding and reactant uniform distribution. The designed serpentine flow field at optimum decreases the maximum temperature gradient across the cell to 10 K to prevent localized hotspots and ensure improved thermal uniformity. Further, the unit power cost for the PEMFC at 333.15 K (60°C) is projected at $0.08/kWh, making it comparable to other conventional sources such as natural gas and coal.