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.

Due to its prominent advantages in long-distance and long-endurance transportation, supersonic civil aircraft has become an important development direction for future civil aircraft. The concept of “green aviation” makes energy saving, emission reduction and noise reduction important optimization design objectives of civil aircraft, which naturally imposes corresponding requirements for its power plant. The traditional configuration power fails to realize the combination of low noise at takeoff, high thrust per unit for super-cruise, low fuel consumption rate and low emission index. Taking the dual-containment Variable Cycle Engine (VCE) configuration with Core Driven Fan Stage (CDFS) as the research object, this study examines the design method of steady state adjustable geometry control law considering key optimization design objectives such as the engine performance, jet noise, and NO_x emission. The research shows that the improvement in the first-containment variable cycle engine is the best way to improve the engine performance, and increase in the first culvert split ratio helps to reduce NO_x emission, while increase in the inner and second culvert split ratios facilites jet noise reduction. The design results are applied to the power unit re-optimization design of the first generation supersonic airliner Concorde. Compared with the baseline scheme, the supersonic cruise fuel consumption rate and the takeoff jet speed are reduced by 20.19% and 44.47%, respectively, enabling the takeoff noise index to meet the airworthiness requirements, under the premise of fulfilling the performance requirements of the aircraft.