脉冲爆震涡轮发动机爆震燃烧室与压气机相互作用及匹配方法

Aimed at the international research front and research difficulties of pulse detonation turbine engines, the interaction mechanism and matching method for the highly transient flow at the inlet of pulse detonation combustor (PDC) and the quasi-steady coming flow from the exit of the compressor is extracted as the key scientific problem and investigated by analytical methods, numerical simulation and experiments. The characteristics and mechanism of the back-propagation pressure waves and reverse flow in a PDC will be analyzed and the methods to suppress the back-propagation pressure waves and reverse flow will be summarized. An innovative method is proposed in this project to isolate the two totally different kinds of flow conditions by utilizing a combination of the shock inside an isolator, the ignition method and valves optimization which could attenuate the peak pressure and the inversed flow at the inlet of the PDC. Furthermore, the detailed flow fields in the compressor and pulse detonation combustor will be observed, such as the shock wave, turbulence and flame structure and other physical and chemical characteristics. The influence of the pressure back-propagation on the working characteristics of the compressor and the characteristics of detonation initiation and back-propagation of the detonation chamber under the variable pressure of compressor outlet will be obtained. On the basis, the interaction mechanism between the compressor and the unsteady flow in the detonation chamber will be achieved. Finally, the steady matching operation between the PDC and the compressor will be realized based on the achieved matching method between the detonation and the compressor. These investigation results can lay a solid theoretical and technical foundation for the design of matching components between the PDC and the inlet/compressor and will further accelerate the development of the new generation air-breathing propulsion system based on the pulse detonation, which has great innovation and scientific significance and application value to support China's aviation engine.

项目瞄准脉冲爆震涡轮发动机研究前沿和难点，提炼出脉冲爆震燃烧室进口周期性、强脉动非稳态流动与压气机出口稳态来流相互作用机理及匹配方法这一关键科学问题，拟从爆震室压力和燃气反传特性及其抑制与隔离方法、爆震室与压气机相互作用、爆震室/压气机的匹配方法与规律等方面开展创新性研究。综合利用理论分析、数值模拟和试验研究，掌握脉冲爆震室的反传特性，形成基于点火方式、爆震室和气动阀/气动机械阀优化设计、激波隔离作用实现压力反传完全隔离的创新方法；在此基础上，观测和分析压气机和爆震室内激波、湍流和火焰结构等物理化学特征，揭示压气机与爆震室内非稳态流动的相互作用机理，获得爆震室反传对压气机工作特性的影响规律及压气机出口变工况下的爆震室起爆和反传特性，形成爆震室与压气机的匹配方法，实现爆震室与压气机的稳定匹配工作，为新型高性能脉冲爆震涡轮发动机的研制奠定理论与技术基础，从而支撑我国在航空发动机领域的科技创新。

为了解决爆震室内周期性、强脉动非稳态流动与压气机出口稳态来流的耦合作用及匹配工作的问题，本项目开展了非稳态脉冲爆震燃烧室与稳态压气机的相互作用及匹配方法与匹配规律研究，为高性能脉冲爆震涡轮发动机的创新发展奠定了坚实基础。.建立了爆震室反传研究数值模型，分别采用高温高压区点火及小能量点火方法，研究了反传的形成及传播特性。设计了内径60mm的模型机，采用汽油为燃料，空气为氧化剂，研究反传压力与工作频率的关系。结果表明：进气段内的反传可以分为压力反传及燃气反传两部分，反传压力影响的范围能够覆盖所计算的整个进气段，反传燃气的影响区域明显小于反传压力；反压峰值随着工作频率的增加而增加。.建立了多循环反压研究的试验系统，系统研究了气动阀、机械阀、点火方式及结构、进气段结构等对反传的影响。建立了三种抑制反传的结构模型，数值研究反压传播特性规律。结果表明：实验探索大幅降低了进气段内的反压峰值及压力脉动；来流总压的大小会影响起爆后反传压缩波的反压强度。.建立轴流压气机、反传抑制结构和爆震室的数值模型，研究分析了反传抑制结构基准模型和反传抑制结构不同结构下爆震室与轴流压气机的相互作用与匹配工作。结果表明：基准模型下的压气机无法正常工作，而优化反传抑制结构下的压气机可以稳定工作。.建立径流压气机与多管脉冲爆震燃烧室试验平台，对不同匹配工作模式下的四管爆震室的压力反传进行了详细分析，结果表明：随着爆震室工作频率的提高，压气机进口空气流量增加，压比升高，转速增大。.本项目揭示了反传生成机理，掌握了降低和隔离压力反传的方法，揭示了爆震室压力反传与压气机相互作用机理，实现了爆震室与压气机的稳定匹配工作。研究成果可用于指导脉冲爆震燃烧室与压气机/风扇的匹配设计，为新一代高性能脉冲爆震涡轮发动机的研制奠定理论与技术基础。