Integrated design of hydrogen-fired turboprop and commuter aircraft

Abstract

Hydrogen for propulsion could lead the industry to achieving the set environmental goals. This work performs a comparative cycle and engine design for a hydrogen-fired and conventional Jet-A burning configuration. Aircraft design and mission performance complete the conceptual design loop. A 19-passenger small commuter aircraft is investigated. A multi-disciplinary framework is developed for the study. A multipoint synthesis scheme is employed for conventional, and hydrogen powered engine assessment. Cryogenic hydrogen tanks and a thermal management system are integrated in the aircraft and their volumetric and gravimetric impact are assessed showing an expected 13% increase of aircraft mass. Direct combustion of hydrogen leads to more efficient and smaller turboprop engines due to the increased specific heat capacity of combustion products. Engine cycle design reveals that the optimum aircraft energy consumption lies at an overall pressure ratio at cruise of 15 and a combustor outlet temperature of 1400 K. However, the hydrogen tanks and fuel conditioning system increase aircraft mass sufficiently to offset the fuel consumption benefits resulting in increased block energy demand between the H2 and Jet-A configurations by 3-4%. This work reveals a lower bound of H2 fuel system gravimetric performance due to aircraft weight certification and highlights the design guidelines for the engine, aircraft, and storage system.