Overall performance and matching mechanism of novel hydrogen supersonic hybrid propulsion system

Supersonic civil aircraft have attracted increasing attention in recent years owing to their broad application potential. However, existing propulsion-cycle concepts still face significant challenges in meeting the performance requirements of supersonic civil transport aircraft. The primary contradiction lies in the difficulty of reconciling the conflicting cycle-parameter requirements associated with high-speed and low-speed operation. A novel hybrid propulsion system for supersonic civil aircraft is proposed, based on a mixed-flow turbofan engine and integrated with hydrogen energy, intercooling heat exchange, and high-temperature fuel cells. A performance simulation model is established for this new propulsion concept, and the matching mechanism of the proposed thermally and electrically coupled cycle is investigated. The proposed propulsion cycle combines the advantages of conventional gas turbines and electric propulsion. The intercooling module alleviates the issue of excessive compressor outlet temperature, while the thermoelectric coupling design mitigates the high aerodynamic and thermal loads imposed on hot-section components under high-power-demand operating conditions. Consequently, the design difficulty of hot-section components is reduced and their operating margin is improved. The equilibrium operating equations of the proposed hybrid propulsion system for supersonic civil aircraft are mathematically derived. Furthermore, based on a newly developed performance model for the hybrid propulsion system using nonlinear component characteristics, the physical essence of the component-matching mechanism is explored, namely the strong coupling and mutual influence between the parameters of the thermal and electrical modules. In addition, the optimization and selection methodology for the key design parameters of the proposed propulsion system is investigated. An optimal overall performance design scheme, obtained using the aforementioned parameter-selection methodology, is then presented together with the corresponding overall performance calculation results. The results indicate that, while satisfying the thrust requirements at all critical operating conditions, the proposed propulsion system achieves a reduction in specific fuel consumption of more than 70% compared with the baseline configuration.