超燃冲压发动机推进性能理论分析

超燃冲压发动机的正推力问题和超声速燃烧的稳定性问题是制约超燃冲压发动机发展的两个关键气动物理问题.虽然经过50多年的研究，但是目前国内外对这两个关键问题的机理还没有研究清楚.文章首次将CJ爆轰理论应用于超燃冲压发动机推进性能分析，给出了这两个关键气动问题的理论分析结果.分析结果表明，燃烧室入口空气静温对发动机的推进性能产生重要影响.当爆轰波的爆速大于隔离段内空气来流的速度时，会向隔离段上游传播，导致发动机不起动.飞行Mach数Ma=6~8是超燃发动机的临界不稳定范围，飞行Mach数Ma>9，超声速燃烧将变得稳定. 

Analysis on the Propulsion Performance of Scramjet Engine

Net thrust and supersonic combustion oscillation are two crucial gas physical issues to scramjet engine, which have not been solved to date. In this paper, the classical CJ detonation theory was first used to analyze the performance of scramjet engine. Results show that the static temperature of air at the combustion chamber inlet influences the pressure of supersonic combustion very much. When the propagation velocity of the combustion wave is greater than the velocity of air in the isolator, it propagates upstream and causes unstart of scramjet engine. The flight Mach numbers of Ma=6~8 are in criti-cal unsteady combustion region for scramjet engine. For flight Mach number Ma>9, the combustion flow field of scramjet engine becomes steady.