Overall Configuration and Performance Analysis of a Turbofan Fuel Cells Hybrid Propulsion System toward Carbon-Neutral Aviation

Fuel cell hybrid power airliners represent a promising option for green aviation transition, offering low retrofit costs and significant emission reductions. However, they face challenges such as limited research and technical difficulties. To address these issues, this paper proposes a novel hybrid propulsion system for trunk and larger aircraft, enabling turbofan engines and hydrogen fuel cells to jointly drive ducted fans. This is achieved by adding hydrogen storage tanks and electrically driven ducted fans to the aircraft, installing a fuel cell system in the nacelle of the turbofan engine, and bleeding air from the turbofan engine’s compressor. Using the long-range wide-body airliner and the first-generation high bypass ratio turbofan engine as retrofit models, the study conducts selection, analysis, and optimization of actual design parameters. When 5% of the compressor inlet air is allocated to the fuel cell system and the fuel cell efficiency reaches 52%, the hybrid propulsion system achieves a relatively high fuel-saving rate with minimal range loss. Under these conditions, the aircraft fuel consumption rate is reduced by 16.06%, the specific impulse is increased by 12.40%, the empty weight of the aircraft is increased by 7.21%, and the maximum range reduction is only 4.36%. Under off-design conditions, the engine exhibits similar trends in throttling, altitude, and velocity characteristics but delivers greater thrust and lower fuel consumption. During a single maximum range flight mission, fuel savings can reach up to 20 tons, corresponding to approximately 13% savings.