Performance and exergy analysis of a NaBH4/Al coupled hydrolysis hydrogen production solid oxide fuel cell hybrid turbofan system with integrated water circulation

To address the escalating electrical power demands, extend endurance, and simultaneously improve fuel economy for unmanned aerial vehicles (UAVs), this study proposes and comprehensively evaluates a novel solid oxide fuel cell hybrid turbofan system. This system innovatively integrates NaBH4/Al coupled hydrolysis for on-board hydrogen generation and features an integrated water circulation system. Thermodynamic models for the engine, reactor, and fuel cell were developed and validated, enabling detailed performance and exergy analyses. Comparative evaluations with a conventional turbofan engine revealed the proposed hybrid system's superior performance, particularly the version incorporating an anode recirculation pump. For instance, at a 35 % electric power fraction, this system achieved a 28.22 % reduction in specific fuel consumption, a 16.95 % increase in thermal efficiency, and a 12.57 % increase in overall efficiency compared to a conventional turbofan. Parametric analyses on fuel cell system, engine, and flight parameters identified optimal operating conditions, with exergy analysis pinpointing the engine combustion chamber as the primary source of irreversible losses. This novel hybrid propulsion system offers a compelling solution for achieving long-endurance, high-efficiency UAV operations with reduced fuel consumption, providing critical technical support for future aviation electrification.