关键词: 航空机载发电, 级间引气, 系统耦合优化, 液氢热管理, 净收益分析

Abstract: Aircraft electrification has raised higher requirements for the power density and operational efficiency of the onboard power system. The traditional auxiliary power unit is currently facing dual bottlenecks of efficiency and emissions. This paper proposes an airborne hybrid power generation system based on liquid hydrogen inter-cooling regenerative heat and inter-stage air introduction coupling for an aerospace fuel cell-gas turbine. The aim is to address the dual bottlenecks of efficiency and emissions in traditional aerospace auxiliary power units. The core innovation of this study lies in: replacing the energy-consuming independent high-pressure air compressor with inter-stage air introduction from the main engine compressor; at the same time, innovatively using liquid hy-drogen cooling energy to inter-cool the high-temperature air and recovering the exhaust turbine residual heat to reheat the hydrogen. The exhaust gas from the fuel cell is catalytically combusted to drive the turbine, achieving stepwise recovery of pressure energy and unreacted chemical energy. The study precisely evaluated the air com-pensation loss using the segmented compression work calculation method and focused on analyzing the impact of key parameters on the system's net benefit. The optimization results show that under typical conditions (exhaust pressure ratio of 7.25, cell temperature of 80 °C, matching the optimal current density, fuel utilization rate and ex-cess air coefficient), the total power generation of the system increases from the initial design of 40.61 kW to 61.31 kW, and the system's net benefit (net power generation minus propulsion power loss) increases from 14.38 kW to 32.19 kW, an increase of 123.8%, and the overall power generation efficiency reaches 55.94%. Thus, this airborne air coupling scheme has certain performance advantages and provides a theoretical basis for the design of hydro-gen-based aerospace hybrid power systems.

Key words: Airborne power generation, Inter-stage bleed air, System coupling optimization, Liquid hydrogen thermal management, Net benefit analysis