Unsteady 3D-CFD Simulation of a Large Active Area PEM Fuel Cell under Automotive Operation Conditions-Efficient Parameterization and Simulation Using Numerically Reduced Models

Polymer electrolyte membrane fuel cells (PEMFC) are promising devices for securing future sustainable mobility. Their field of application ranges from locally emission-free stationary power generation to propulsion systems for vehicles of all kinds. Computational fluid dynamic (CFD) simulations are successfully used to access the internal states and processes with high temporal and spatial resolution. It is challenging to obtain reliable physical values of material properties for the parameterization of the numerous governing equations. The current work addresses this problem and uses numerically reduced models to parameterize sophisticated transient 3D-CFD models of a commercial PEMFC. Experimental data from a stack test stand were available as a reference for numerical optimization of selected parameters and validation purposes. With an innovative meshing approach, the homogenized channels approach, a reduction of computational cells by 87% could be achieved, thus enabling the unsteady simulation of a 120 s load step with a computational mesh that represents the entire fuel cell geometry with reasonable computational effort. The water formation and the transport processes during the load step were analyzed. The self-humidification strategy of the fuel cell gases was visualized and the uniformity of the simulated quantities was discussed. An outlook on possible future work on efficient parameterization is given.