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采用带化学反应的非定常数值仿真方法,对爆震发动机(PDE)内进气道、燃烧室、尾喷管的耦合流场进行了分析,并着重研究了爆震压力波及其反射波对超声速进气道内流动结构的非定常干扰过程,对比了3种进气道/燃烧室耦合方式下进气道流动特性的差异.结果表明:通过在燃烧室内填充以化学恰当比预混的燃料和氧化剂,数值仿真可获得稳定自持的爆震波.在爆震波压强作用下所产生的结尾波系和反射激波会发生耦合干扰作用,它们在流道内的运动传播影响了结尾波系的前传幅度.通过对比不同进气道/燃烧室耦合方式的流场特征发现:采用突扩式进气道/燃烧室连接段可利用燃烧室头部固壁的阻碍以及其对爆震高压波的反射作用将大部分的压缩气体存储于燃烧室内,进而减弱进气道与燃烧室之间的耦合干扰作用,对提高进气道的工作稳定性有利.另外,内凹式燃烧室头部段的引入还为压缩气体提供了额外的存储空间,故可以进一步缓冲爆震高压,提高进气道的稳定工作裕度.
The unsteady numerical simulation method with chemical reaction was used to analyze the coupled flow fields of the inlet, the combustion chamber and the tail pipe in the detonation engine (PDE). The effects of the pressure of the detonation and the reflected wave on the supersonic velocity The difference of flow characteristics between the three inlet / combustor ports was compared with the unsteady flow of the in-port flow structure.The results show that by filling the combustion chamber with chemically and properly pre-mixed fuel and oxidizer , The numerical simulation can obtain stable and self-sustaining detonation wave.The coupled wave and reflected shock wave generated by the pressure of detonation wave will have coupling interference and their propagation in the flow channel will affect the amplitude of precession of the ending wave system.Through Comparing the flow field characteristics of different inlet / combustor couplings, it is found that the use of sudden expansion of the inlet / combustor connection can obstruct the blocking of the solid wall at the head of the combustor and its reflection effect on the high pressure wave of the knocking. Part of the compressed gas stored in the combustion chamber, thereby reducing the interference between the intake port and the combustion chamber coupling, to improve the working stability of the inlet is advantageous.In addition, the concave combustion chamber Introduction section also provides additional storage space for the compressed gas, it is possible to further cushion the knock pressure, improve the stability margin of the air intake.