NAFEMS Americas and Digital Engineering (DE) teamed up (once again) to present CAASE, the (now Virtual) Conference on Advancing Analysis & Simulation in Engineering, on June 16-18, 2020!

CAASE20 brought together the leading visionaries, developers, and practitioners of CAE-related technologies in an open forum, unlike any other, to share experiences, discuss relevant trends, discover common themes, and explore future issues, including:
-What is the future for engineering analysis and simulation?
-Where will it lead us in the next decade?
-How can designers and engineers realize its full potential?
What are the business, technological, and human enablers that will take past successful developments to new levels in the next ten years?

Resource Abstract

Hydrogen technologies are considered as a valid alternative to decarbonize the transportation sector, especially for trucks and trains. Energy capacity and fast-refueling represent fuel cells most attractive aspects when compared to lithium batteries. However, several challenges still need further research and development. Internal reactions in fuel cells are promoted by Platinum (Pt), which increases the final cost of the system. PEMFC working at high current densities need less platinum, but face performance issues. In particular, the reassociation reaction of hydrogen-electrons-oxygen at the cathode side produces liquid water, which prevents reactants to effectively reach the membrane. In addition, the membrane needs to work at an ideal water content. Membrane drying-out impacts the overall efficiency and reduces the lifetime of the system. Understanding such phenomena through experimental test cases is costly and cumbersome as measurement of two-phase flows are needed in a very narrow environment. For instance, neutron radiography is able to provide insights on the water production among the several fuel cells layers whilst gas chromatography can be used to for water saturation measurement. Both techniques are though expensive. In this work, advanced CFD techniques are used to study the formation of liquid water inside the fuel cells component and understanding the impact of geometry on such physics. A portion of a single cell layer with five channels is simulated in Simcenter STAR-CCM+. The channels follow a wavy pattern, which allow for a more homogeneous temperature distribution. The equations of flow are solved for the channels and the gas diffusion layers (GDL), the latter being considered as porous media. Bipolar plates are modelled as a solid able to conduct electricity and ohmic heat. The membrane is modelled as a solid including water transport and proton with electro-osmotic drag as well as ohmic heating from the electrochemistry reactions, calculated at the infinitely thin layer between the GDL and the membrane itself. A two-phase approach is included to model the gas mixture and liquid water transport in the GDL and channels. The two geometries present very similar polarization curves but significant differences in terms of water production and electric density gradients are shown. A study on the way hydrogen is consumed and reacts on the anode side is also included, providing insights on the complex physics of fuel cells.