Author: HongBin Zheng (Beihang University) - Liquid hydrogen (LH2) emerges as a transformative solution for sustainable aviation, offering unique advantages as a zero-carbon energy carrier with exceptional specific heat capacity and cooling capabilities. While hydrogen fuel has been extensively investigated for gas turbine applications, existing fuel systems continue to demonstrate significant limitations, particularly in fuel thermal management efficiency. This research presents an innovative thermal management system that synergistically integrates a Rankine cycle and H2 direct expansion cycle (RC-DEC) with turbofan engine operations to enable coordinated recovery of LH2 cryogenic energy and multi-stage waste heat from engine core components. Through systematic exploration of waste heat utilization strategies for diverse temperature-grade sources within the engine, we have developed an advanced combined thermal management architecture incorporating intercooling and exhaust heat recovery. This novel configuration achieves superior energy matching through optimized thermal stratification and cascade utilization of heat sources. Simulation results demonstrate the system's capability to harmonize the advantages of distinct thermal management approaches, yielding simultaneous performance enhancements in both the power generation and propulsion systems. The RC-DEC system attains an exergy efficiency of 33.9% with a net power output of 2847.2 kW, while the engine exhibits a 5.55% thrust improvement at the design point. This study establishes a comprehensive energy management framework for next-generation hydrogen-powered aircraft propulsion systems, offering critical insights for achieving decarbonization targets through advanced thermodynamic integration of cryogenic fuels and optimized waste heat recovery strategies. The findings contribute to the development of sustainable aviation technologies, aligning with global efforts to mitigate the environmental impact of air transportation.
