Engine-aircraft trade-offs in reconfigurable hydrogen turbofan thermal management

Abstract

Hydrogen-fuelled turbofan engines can reduce aviation emissions, but their mission benefit is constrained by the integration of liquid‑hydrogen storage and thermal-management hardware. This study develops a coupled engine-aircraft evaluation framework to quantify the propulsion and aircraft-level effects of liquid hydrogen (LH₂) heat-sink utilisation. Four thermal-management configurations are analysed: the pre-cooling, heat-recovery, cooled-cooling-air (CCA), and integrated configurations. They are evaluated using thermodynamic cycle modelling, exergy analysis, and endurance-based mission assessment. The results show that heat-sink utilisation reduces thrust-specific fuel consumption and improves exergy efficiency by redistributing thermal loads within the engine. The integrated configuration provides the most balanced improvement by combining low- and high-temperature heat absorption, but aircraft-level gains are limited by storage and heat-exchanger mass. For a 70-seat regional aircraft, endurance-oriented optimisation reduces hydrogen fuel consumption by 15.4% and increases endurance by 8.98%, while propulsion-system mass increases by 24.4%. Sensitivity analysis indicates that a hydrogen-storage-system gravimetric efficiency of 24.51%, defined as the usable LH₂ mass divided by the combined mass of usable LH₂ and the empty tank, is required to achieve endurance parity with a kerosene baseline. The optimal flow-allocation strategy also differs between cruise and take-off, demonstrating the need for reconfigurable thermal management in hydrogen-powered aviation.