Airborne Hydrogen Fuel Cell Propulsion System Dynamic Performance Model

Decarbonizing the aerospace industry is a key step to meeting overall climate change mitigation efforts and hydrogen as a fuel source will be critical to achieving those goals and has been shown feasible as a propulsion source for aircraft. PiAC is developing an efficient high temperature hydrogen fuel cell propulsion system for integration into VTOL aircraft and as part of the development process will create a dynamic model of the propulsion system for evaluation of performance and safety considerations. The Phase I feasibility study showed that hydrogen fuel cell propulsion is a viable option for a UAM application, and that utilizing liquid hydrogen storage provides better range and cost performance than even the conventional internal combustion engine. Phase I research identified a conceptual layout for integration of the propulsion system, estimated acquisition and operating costs, and showed significant greenhouse gas abatement for the fuel cell variant. The system architecture designed in Phase I will be used to structure a dynamic model of the hydrogen fuel cell propulsion system in Phase II. Components to be included in the model will make-up the full propulsion system, from reactant supply (hydrogen and oxygen) to delivery of electrical power. A key aspect of the PiAC hydrogen fuel cell design is that it operates at high temperatures which in turn requires less cooling. This is an emerging technology which still requires significant research and development. Primary objectives of the Phase II effort are to develop a tool which emulates a physical propulsion system and can evaluate transient aircraft conditions, time responses of component hardware, reaction to degraded or faulted conditions, and validation of test data. A model of this caliber will benefit multiple PiAC programs and be useful to DOE engineers/scientists with evaluation of high temperature fuel cell systems within their portfolio. Additionally, this model will be used for failure analysis consistent with FAA certification efforts. As the FAA develops its requirements for hydrogen fuel cell propulsion systems, PiAC can align our design and development goals to meet those requirements. Airborne application of hydrogen fuel cell propulsion systems has potential to disrupt the current commercial aerospace market. In addition to the environmental implications of a zero-emission platform, the direct operating costs of the propulsion system are significantly less than conventional internal combustion or turbine engines. Additionally, noise levels are significantly reduced compared to fossil fuel burning engines which is critical for adoption into a UAM market.