超音速燃烧室中激波/化学反应相互作用机理

In order to meet the need of basic theory of hypersonic propulsion and optimize the performance of supersonic combustor, interactions between shock-wave and chemical reactions will be deeply studied by theory analysis, experimental research and numerical simulation. In the experimental study, high frequency wall pressure measurement system, high speed schlieren and photography apparatus and OH planar laser-induced fluorescence imaging technique will be used to obtain the characteristic of supersonic flow(distribution of pressure, instantaneous structure of shock-wave train) and instantaneous structure of flame in the supersonic combustor. The studies will emphasis on the development of shock-wave train and flame under different flow conditions of inlet in the combustor and different equivalence ratio of fuel. The relationship between shock-wave and chemical reactions will be analyzed and discussed. The massive parallel computing system will also be used to simulate the interactions between flow and combustion in the supersonic combustor. The detailed chemical kinetic model will be adopted to simulate the phenomena of the interactions. The numerical simulations will be testified and validated by the experimental data. At last, the mechanism of the interactions will be explored by the integrated results of the experimental studies and numerical studies. Based on the mechanism, we will figure out the effect of this mechanism on the characteristic of ignition and combustion and will propose a scheme to optimize the performance of supersonic combustor.

基于高超声速推进技术基础理论研究的需要，针对超音速燃烧室性能优化，本项目采用理论、试验和数值模拟方法研究着火与火焰稳定过程中激波/化学反应的相互作用机理。在脉冲燃烧风洞中采用高频测压系统、高速纹影诊断技术以及平面激光诱导荧光技术“OH-PLIF”获得动态流场特征（压力分布、激波串结构等）和超音速燃烧室中的火焰结构，重点研究不同来流条件以及燃料参混比时激波串与火焰的发展历程，理论分析动态过程中激波与化学反应的相互影响。利用高性能计算机集群开展流动与燃烧的耦合计算，采用详细的化学反应动力学模型模拟试验中激波/化学反应的相互作用过程并与试验结果进行对比验证，综合试验以及数值计算结果，深入揭示激波/化学反应的相互作用机理。在此基础上明确这种相互作用机理对超音速燃烧室着火以及稳定燃烧的影响区域，提出超音速燃烧室的性能优化方案。

本项目研究了超音速燃烧室的激波与化学反应的相互作用机制，通过实验以及大规模数值计算分别研究了氢气燃料以及乙烯燃料在超音速燃烧室燃烧过程的燃烧特性与流场特性相互影响的结果。采用了高频压力测量系统、高速纹影系统以及OH-PLIF系统分别对超音速燃烧室压力变化、流场结构变化以及化学反应区域进行了实验测量。研究结果表明化学反应与流场激波存在较强的耦合作用关系，随着燃料的点火引燃，燃烧与主流激波结构产生了相互促进关系，燃烧的发生会导致激波前移并增强，而增强的激波反过来又使剪切层燃料参混区温度升高，加快了燃料的燃烧化学反应，促使燃烧增强以及燃烧区域扩大。燃烧的增强与扩大又重新使流场进行变化匹配，激波继续前移与增强，往复循环，最后达到平衡稳定。采用半详细化学反应动力学机理进行对超音速流场进行耦合计算，利用大规模并行计算机开展了数值模拟研究，计算结果与实验结果相符，计算结果同样证明了实验结果，并在反应基团上给出了发生燃烧反应的主要基团OH分布变化与流场结构的变化分析，获得了中间基团OH的化学反应与主流激波存在相互促进作用。