Towards design- and operating-point selection for fuel cell cathode air-supply systems in aviation

抄録

In this paper, a hydrogen fuel cell-based propulsion system for regional and future mid-range aircraft is investigated. The main focus herein lies on the exploration of the operating range of the cathode gas supply system of the fuel cell stack. Subsequently, resulting constraints that limit the design space of the entire propulsion system are shown. Investigations are carried out using the on-design thermodynamic cycle calculation module of the in-house software ASTOR (AircraftEngine Simulation for Transient Operation Research). It includes a fuel cell model which facilitates conservation of mass and energy along the cathode side of the fuel cell system, as well as the specic constraints of the fuel cell stack due to its operating conditions. The second objective of this study is to determine suitable design points for the cathode air supply system which will serve as the starting point for detailed design of turbo components. Optimum fuel cell operating conditions are identied throughout relevant operating points at constant stoichiometry. Furthermore, contradictory requirements of the air supply system in terms of compressor mass ow and pressure ratio are identied. Finally, the off-design performance is estimated in order to derive statements about the coverage of the operating range depending on the choice of the design point. The top-of-climb operating point may be chosen as the design point in order to cover most operating points. At the same time, high altitude operation with a constant-geometry system appears only feasible at unrealistically high stoichiometic ratios or with additional measures such as bleed valves downstream of the compressor.