推进动力系统燃烧不稳定性产生的机理、预测及控制方法

Mechanism,prediction and control method of combustion instability in propulsion system

关键词:  热声不稳定  燃烧不稳定  穿孔板  不稳定频率

Key words:  Thermoacoustic instabilities  Combustion instabilities  Perforated liner  Unstable frequency

摘要:

在不稳定热释放和声波相互耦合作用下而产生的燃烧不稳定现象,表现为振荡燃烧的形式,常发生于火箭发动机、航空发动机加力燃烧室以及地面燃气轮机等装置当中,会对结构引起很严重的破坏。本文总结了当前关于燃烧不稳定问题的机理以及控制方法的研究进展。目前来看,关于燃烧不稳定的机理研究方面,包含实验研究以及数值方法研究。实验方面,有rijketube热声不稳定实验,还有模拟真实燃烧室环境的燃烧实验。数值方面的工作,包括线化的热声不稳定模型,以及对火焰进行描述的解析模型和大涡模拟等方面的工作。同时,人们尝试了各种抑制不稳定的方法。控制方法包含两大类,即:主动控制方法以及被动控制方法。主动控制方法在理论研究方面取得了重大成果,然而,由于其实现上需要复杂响应系统、执行机构,因此,距离实际工程应用还很遥远。而被动控制方法,例如,亥姆赫兹共振腔,以及穿孔板等装置,在工程上得到了很好的应用。

Abstract:

Thermoacoustic instabilities are characterized by large-amplitude oscillations for the interactions between acoustics and unstable heat releases.Such instabilities have been encountered in rockets engines,afterburners and gas turbines in the form of combustion instabilities.Sometimes it would bring structure damages.Review about investigations on Mechanisms and control method of the combustion instability is conducted.By now,a lot of work has been done on the mechanics of these instabilities,such as numerical and experimental investigations.The numerical investigations include one dimensional,three dimensional analytical thermoacoustic instability model,and LES on unsteady flame heat release.And experimental studies include rijke tube and real combustors,and so on.Under these investigations,the ultimate purposes are the effective control methods to the instabilities.By now,the control methods include passive and active methods.Active method is successful in theory but it has a long way to go to be applied in engineering because it always includes very complex executive system.The passive methods,such as Helmholtz resonator and perforated liner,have been widely used in practice.