超燃冲压发动机是航空航天动力的又一次历史性的跨越，是国家的重大战略需求。本项目面向超燃冲压发动机的宽工况性能需求，在讨论发动机热力循环结构及约束条件的基础上，针对性地提出了复合等静温热力循环，从本质上来扩展发动机热力循环的极限性能边界，揭示发动机中主导燃烧过程及热力循环结构随工况变化的热力学演化机理，获取超燃冲压发动机热力循环的极限性能边界，为超燃冲压发动机技术的发展提供科学依据和技术途径。

Scramjet is a historic leap for the development of air-breathing propulsions, and also an important need for country strategies. Considering the performance requirement of scramjet for a wide range working condition, this project in details describes the characteristics of scramjet engine thermodynamic cycle and its constraints, and proposes a composite-isostatic -temperature thermodynamic cycle which can be used to essentially extend the engine performance limits. This work will reveal the evolution process of scramjet thermodynamic cycle for different working conditions, as well as provide limited performance boundary for scramjets. Such work will provide more scientific basis and technical approaches for the development of scramjet technologies.