脉冲爆震火箭发动机应用基础问题研究进展

脉冲爆震火箭发动机是一种通过产生周期性爆震波获得推力的动力装置，具有热效率高、结构简单、适用范围广等潜在优点。在面向应用时，为了充分发挥脉冲爆震火箭发动机的优势，需要解决诸多理论及工程性问题。目前已有大量的研究正在建立统一的爆震推进理论体系，以期为基于爆震推进方式的问世奠定理论和技术基础。针对应用可能遇到的问题，介绍了国内外相关研究进展。主要内容包括:两相爆震发动机技术，短距低阻起爆技术，发动机性能优化以及PDRE样机实验。关于两相爆震发动机技术，主要介绍了液态燃料爆震燃烧时的速度损失，液态燃料的雾化以及与气态氧化剂的掺混，最新进展包括通过加热燃油提高其雾化性能，从而提高推进性能；关于短距低阻起爆技术，主要介绍了固体障碍物起爆、流体障碍物起爆、热射流起爆以及激波聚焦起爆这4种方式的最新进展，其中固体障碍物起爆技术最为常见，而采用流体障碍物起爆技术可以更多地降低起爆过程中的性能损失；关于发动机性能优化，主要介绍了部分填充效应、尾喷管技术以及高频控制技术，部分填充以及尾喷管的使用有利于推进性能的提升，但在设计理论上仍需要更深入的研究，目前采用无阀工作方式可以有效提高发动机的工作频率；关于样机集成，主要介绍了目前出现的脉冲爆震发动机样机以及相关实验研究。

Progress in the basic application issues of the pulse detonation rocket engine

The pulse detonation rocket engine is a propulsion system which obtains thrust by repeatedly generating detonation waves. It has the potential advantages of high thermal efficiency, simple structure and wide applications. In order to realize the potential advantages, various theoretical and engineering problems need to be solved before it goes into practical application. Numerous efforts have been made to establish a systematic set of theories and guidelines that could be universally applied to detonation-based propulsion designs, thereby laying solid theoretical and technical foundations for the birth of novel aerospace propulsion engines. The progress in some basic application issues in the past few decades is summarized, including the two-phase de-tonation engine technology, short-distance and low-loss detonation initiation technology, perfor-mance optimization and prototype integration. For the two-phase detonation engine, researches on the velocity deficit in two-phase detonation and researches on the atomization and fuel-oxidizer mixing are introduced. Some new ideas are developed in recent years. To pursue a better propulsion performance, liquid fuel is pre-heated to improve the atomization performance. For the short-distance and low-loss detonation initiation, researches on the detonation initiation improvements using solid obstacles, fluidic obstacles, hot jet or shock focusing are involved. Employing solid obstacles is the most common technology used in the pulse detonation engine, whereas employing fluid obstacles can accelerate the detonation initiation with lower loss of propulsion performance. For the performance optimization, the partial filling effect, high efficient nozzles and high frequency operation technologies are discussed. Partial filling and proper nozzles are proved effective to enhance the propulsion performance, while more accurate theory is needed. Recent researches indicate that pulse detonation engines can reach a high operating frequency in the valveless mode. For the prototype integration, a few pulse detonation rocket engines launched by different institutions and the relevant experimental researches are introduced as well.