微穿孔板抑制不稳定燃烧的声学数值仿真

为了研究微穿孔板吸声结构对不稳定燃烧的抑制作用,采用高精度的计算气动声学(Computational Aeroacoustics,CAA)方法开展时域下的数值仿真。首先对带有压力时滞模型的三维声学扰动方程进行求解,给出发动机不稳定燃烧的频率信息。然后通过解析模型分析微穿孔板吸声结构的阻抗特性,并由多自由度宽频阻抗模型模拟微穿孔板对该不稳定频率的抑制作用。仿真捕捉到的不稳定燃烧频率与地面试车测得的频率相一致。表明采用的计算气动声学方法及相应模型可以准确地捕捉不稳定燃烧的频率信息,并分析微穿孔板对不稳定燃烧的抑制作用,对于工程上快速预测不稳定燃烧具有一定意义。 

Acoustic numerical simulation of a micro-perforated panel absorber for combustion instability suppression

Time-domain numerical simulation was performed by a high order computational aeroacoustics (CAA) approach in order to research the suppression of a micro-perforated panel absorber on combustion instability. Firstly, three dimensional acoustic perturbation equations with pressure time lag model were solved and frequencies of the engine were predicted. Then the acoustic impedance characteristic of a micro-perforated panel absorber was analyzed by an analytical method. A time-domain numerical simulation was carried out by multi-freedom broadband impedance model in order to research the impedance characteristic. The frequency predicted by numerical simulation showed good consistency with the experimental result. It is demonstrated that the computational aeroacoustics approach can recognize dangerous modes and analyze the suppression of a micro-perforated panel absorber on combustion instability, which can provide some reference for the engineering design of liquid rocket engine.