面向空天发动机的爆震燃烧的应用基础研究

In order to meet the increasing demands for high efficiency and payload for aerospace vehicles, advanced propulsion systems are required to possess high propulsion performance in their wide working ranges with multi-mode operation. Detonation-based propulsions have the potential to attain the goal because of their considerably high energy release rate and thermal cycle efficiency. According to different initial and operating conditions, detonations that could be potentially utilized for aerospace propulsion can be divided into various types. And, the present project aims to carry out a systematic investigation on how to initiate these detonations efficiently within a shortest Deflagration-to-Detonation Transition (DDT) distance and how to propagate self-sustained effectively. When tackling this critical, core scientific problem, the real factors which are related with the practical detonation-based engines, such as the incoming flows with wide speed range, the confined space for detonations to evolve, and the non-ideal propagation of detonations will be taken into account. By investigating the formation, evolution and quenching mechanisms of these detonations in the combustor flows, the criteria for the effective initiation of detonations in a short distance and the limit range for the self-sustained, steady propagation of detonations will be proposed in this work. Based on the universal principle of total energy conservation, a high efficient approach of utilizing the energy will be obtained. Also, the models to estimate the propulsion performance of detonation-based engines will be established by examining the energy release competing with various losses. Finally, in terms of the incoming flow, the operation, and output conditions, the transition process between different modes of detonations will be revealed and its corresponding control scheme will be proposed. The ultimate goal of this project is 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.

空天飞行器的经济性和载荷需求对推进系统提出了高性能、宽空域、宽速域和多模态工作等苛刻要求，爆震推进正是适合的新型燃烧和热力循环方式。针对可能用于空天推进的多种形式的爆震燃烧，包括顺流和逆流传播的脉冲爆震、驻定斜爆震、连续旋转爆震、微尺度的爆震燃烧波，围绕“短距起爆与自持机理”这一核心科学问题开展研究，特点是考虑发动机应用的实际情况，如宽速域来流、受限空间、非理想传播等，掌握宽速域来流和多尺度受限空间内各型爆震形成、演化、稳定及熄灭机理，提出适合空天动力应用的可靠短距起爆准则和自持稳定传播极限；基于系统总能量守恒提出爆震燃烧的能量高效利用方法，从能量释放/损失理论角度建立各型爆震发动机的性能模型；根据各型爆震波的来流、工作及出口条件探索模态转换规律与调控方法。力求建立统一的爆震推进的理论体系，为新型空天推进方式的问世奠定理论和技术基础。

爆震推进装置可以作为一种未来空天飞行器高性能动力装置，同时满足高性能、宽空域、宽速域和多模态工作等苛刻要求。针对可能用于空天推进的多种形式的爆震燃烧，旨在掌握宽速域来流和多尺度受限空间内各型爆震形成、演化、稳定及熄灭机理，提出适合空天动力应用的可靠短距起爆准则和自持稳定传播极限；掌握基于系统总能量守恒提出爆震燃烧的热功转化原理及能量高效利用方法，从能量转换机制角度建立各型爆震发动机的动力性能模型；根据各型爆震波的来流、工作及出口条件探索模态转换规律与调控方法。.本项目已经取得了以下系统研究成果：1）获得了静止条件下光滑管中起爆过程的机理，提出了利用预爆管内的过驱爆震来起爆主爆震室混合物的方法，发现了不同的爆震起爆模式，总结出定量的临界起爆条件；掌握了超音速来流条件下受限及非受限空间内起爆机理和旋转爆震发动机RDE中起爆和熄爆机理；提出并掌握了热射流起爆、流体障碍物起爆等短距起爆技术，解决了不同形式爆震发动机中的起爆问题；2）进行了基于两相脉冲爆震发动机PDE的热管理研究，提出了基于质量能量守恒的再生冷却系统设计方法和用于优化PDE推进性能的流体喷管设计理论；建立了斜爆震发动机ODE和RDE的性能分析模型，获得了RDE在不同工作模态下的推力特性；3）突破了不同形式爆震发动机稳定工作的控制难题，包括脉冲爆震火箭高频工作的实现和调控问题，两相脉冲爆震工作频率达到世界最高140Hz；吸气式爆震发动机APDE压力反传问题，掌握了抑制反传机理；驻定爆震发动机SDE爆震波驻定及调控问题以及RDE的模态转换与控制问题。.综上所述，本项目完成了既定的研究目标，掌握了爆震发动机的急速起爆、高效用能和可控运行三方面的规律，建立起了爆震发动机的理论体系，获得了预期的研究成果，为爆震推进的工程应用奠定了理论和技术基础。