These slides were presented at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

On the road to aircraft decarbonization, new propulsion concepts are designed and virtually assessed. One possibility is using carbon-free fuels like hydrogen, which is currently experiencing a lot of popularity, in part due to the European research program Clean Aviation. Within the European-founded project NEWBORN, a consortium led by Honeywell International s.r.o is working on a Fuel cell (FC) system demonstrator with several partners. In parallel to the real demonstrator, a Digital Twin (DT) is necessary to support design activities from the preliminary stage up until final control validation. A key challenge is the management of hydrogen in a complex and harsh environment. The fuel must be maintained in the liquid phase in a cryogenic tank and provided to the fuel cell anode in a gaseous phase at the correct pressure and temperature. Leakages need to be avoided within the whole system to prevent the buildup of explosive atmospheres. Special controls and actuators are necessary to ensure the safety and reliability of the system. Heat fluxes into the tank need to be minimized to reduce vaporization, and therefore hydrogen losses. This is accomplished by encompassing all necessary peripheral equipment (e.g. valves, sensors, heaters for preconditioning) in two equipment bays, the so-called 'œcold box' and 'œhot box', that are attached to the tank and isolated from the environment. Every component that is part of the system is modeled within Simcenter Amesim at different levels of fidelity to analyse its performance. All these components make up the H2 line and are depicted within the digital twin, including a hydrogen recirculation loop for the fuel cell with its associated model, to allow faster control calibration and some failure mode analysis. Thanks to this simulation work, component design is enhanced and allows easier component integration within the complete system, especially in the context of short planning execution as is necessary in the NEWBORN project. The development of such a subsystem model supports the understanding of complex hydrogen physics as well as the interaction with other subsystems at an aircraft-system level to create a fully completed and validated fuel cell system digital twin. Another key element is the possibility of assessing various configurations for the hydrogen line and selecting the one that fulfills all requirements while delivering the best performance. The simulation model will be then validated with test measurements, once preliminary components, and later the integrated system, are completed. The objective is to ensure confidence in the fuel cell digital twin. The digital twin will then be run in parallel with the final demonstrator to showcase and highlight the complementarity of both approaches, before going further in a real flying demonstrator, which could be the next step in this research activity. In conclusion, using a digital twin during the development of new technologies, such as the hydrogen system presented in this work, can help to gain a better understanding the processes and interactions within the system and therefore find better designs and solutions for the tasks at hand, while simultaneously accelerating the development process.