Abstract Hypersonic airbreathing propulsion is one of the top techniques for future aerospace flight, but there are still no practical engines after seventy years' development. Two critical issues are identified to be the barriers for the ramjet-based engine that has been taken as the most potential concept of the hypersonic propulsion for decades. One issue is the upstream-traveling shock wave that develops from spontaneous waves resulting from continuous heat releases in combustors and can induces unsteady combustion that may lead to engine surging during scramjet engine operation. The other is the scramjet combustion mode that cannot satisfy thrust needs of hypersonic vehicles since its thermos-efficiency decreases as the flight Mach number increases. The two criteria are proposed for the ramjet-based hypersonic propulsion to identify combustion modes and avoid thermal choking. A standing oblique detonation ramjet (Sodramjet) engine concept is proposed based on the criteria by replacing diffusive combustion with an oblique detonation that is a unique pressure-gain phenomenon in nature. The Sodramjet engine model is developed with several flow control techniques, and tested successfully with the hypersonic flight-duplicated shock tunnel. The experimental data show that the Sodramjet engine model works steadily, and an oblique detonation can be made stationary in the engine combustor and is controllable. This research demonstrates the Sodramjet engine is a promising concept and can be operated stably with high thermal efficiency at hypersonic flow conditions.

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高超音速呼吸推进的标准及其实验验证

摘要高超音速呼吸推进是未来航天飞行的一项重要技术，但经过70年的发展，仍然没有实用的发动机。确定了两个关键问题是基于冲压发动机的发动机的障碍，该发动机已被视为数十年来超音速推进最有潜力的概念。一个问题是上游行进的冲击波，该冲击波是由燃烧室中连续放热产生的自发波产生的，并且会引起不稳定燃烧，从而可能导致超燃发动机在超燃发动机运转期间发生喘振。另一种是超燃冲压发动机燃烧模式，无法满足高超音速飞行器的推力需求，因为其热效率会随着飞行马赫数的增加而降低。为基于冲压发动机的超音速推进提出了两个标准，以识别燃烧模式并避免热阻塞。基于该标准，提出了一种立式斜爆燃冲压喷气发动机（Sodramjet），其概念是用斜向爆燃代替扩散燃烧，而斜向爆燃自然是一种独特的压力增加现象。Sodramjet发动机模型是使用多种流量控制技术开发的，并已在高超声速飞行复制的冲击隧道中成功进行了测试。实验数据表明，Sodramjet发动机模型运行稳定，并且可以使倾斜爆炸在发动机燃烧室中保持静止并且是可控的。这项研究表明，Sodramjet发动机是一个很有前途的概念，可以在高超声速流动条件下以高热效率稳定运行。基于该标准，提出了一种立式斜爆燃冲压喷气发动机（Sodramjet），其概念是用斜向爆燃代替扩散燃烧，而斜向爆燃自然是一种独特的压力增加现象。Sodramjet发动机模型是使用多种流量控制技术开发的，并已在高超声速飞行复制的冲击隧道中成功进行了测试。实验数据表明，Sodramjet发动机模型运行稳定，并且可以使倾斜爆炸在发动机燃烧室中保持静止并且是可控的。这项研究表明，Sodramjet发动机是一个很有前途的概念，可以在高超声速流动条件下以高热效率稳定运行。基于该标准，提出了一种立式斜爆燃冲压喷气发动机（Sodramjet），其概念是用斜向爆燃代替扩散燃烧，而斜向爆燃自然是一种独特的压力增加现象。Sodramjet发动机模型是使用多种流量控制技术开发的，并已在高超声速飞行复制的冲击隧道中成功进行了测试。实验数据表明，Sodramjet发动机模型运行稳定，并且可以使倾斜爆炸在发动机燃烧室中保持静止并且是可控的。这项研究表明，Sodramjet发动机是一个很有前途的概念，可以在高超声速流动条件下以高热效率稳定运行。