Modeling and Evaluation of LH2 Conditioning Concepts in the Exhaust Gas Stream of Aircraft Engines

Abstract

The present thesis investigates hydrogen conditioning concepts for application in aero engines. Several architectures are modeled within the virtual engine framework GTlab, where the hydrogen’s thermal management system with compressors, pumps, and heat exchangers is implemented. The study focuses on integrating an exhaust gas recuperator to exploit available waste heat, complemented by an oil-cooler and an environmental control system heat exchanger. A secondary fluid is utilized to facilitate the transfer of heat from these sources to the hydrogen heat exchanger. This process ensures maintaining suitable hydrogen injection temperatures for stable combustion, additionally preventing heat exchanger icing. Within the scope of this investigation, both Design (cruise) and Off-Design (take-off) points are analyzed for the conditioning architectures. In Design, the influence of hydrogen injection temperature on heat exchanger sizing is assessed, with a further examination of its consequent conditioning behavior under varying boundary conditions in Off-Design. The analysis highlights trade-offs between high hydrogen temperatures, compact heat exchanger design, and additional compressor power consumption. The results of this study indicate clear tendencies toward architectures that combine favorable thermal performance with reduced component size, thereby supporting more efficient hydrogen based propulsion concepts. This work establishes a foundation for the hydrogen conditioning of aero engines and provides a framework for future research in this field.