The acoustic field of a turbulent lean cpremixed open flame is numerically investigated by a hybrid method solving the Navier-Stokes equations in a large-eddy simulation formulation and the acoustic perturbation equations. The interaction of acoustic modes of a burner plenum and the turbulent flame is analyzed with respect to the sound emission of the flame. It is investigated if a simplified computation yields a good broadband agreement of the sound pressure spectrum with experimental measurements. The results of two numerical setups, i.e., the first configuration consists of the burner plus the plenum geometry while in the second configuration the plenum is neglected, which is often done in technical applications due to computational efficiency reasons, are compared with experimental findings. It can be concluded that the plenum has a pronounced impact on the dynamics and combustion noise of the open flame. To be more precise, the comparative juxtaposition of the numerical and experimental results shows a good agreement only for the full burner-plenum computation since the interaction of the acoustic quarter-wave modes of the burner plenum with the jet flow has to be captured. The interaction of these quarter-wave modes with the flow is analyzed and the acoustic response to heat release fluctuations of the flame of the full burner-plenum computation is compared to that of the simplified burner computation, in which the plenum acoustics is neglected. Due to the excitation by the plenum acoustics, the jet flow of the full burner plenum contains higher turbulent kinetic energy and the flame is excited at several additional frequencies which result in distinct peaks in the acoustic spectrum and a higher overall sound pressure level.

通过混合方法求解大涡模拟公式中的Navier-Stokes方程和声扰动方程，对湍流稀薄的预混明火的声场进行了数值研究。相对于火焰的声发射，分析了燃烧器增压室的声学模式与湍流火焰的相互作用。研究了简化的计算是否可以通过实验测量得出声压谱的良好宽带协议。将两个数值设置的结果（即第一种配置由燃烧器加气室几何形状组成），而在第二种配置中忽略气室（由于计算效率原因，在技术应用中通常这样做）与实验结果进行比较。可以得出结论，气室对明火的动力学和燃烧噪声有显着影响。更准确地说，数值和实验结果的并列比较表明仅对于完整的燃烧室-气室计算，这是一个很好的协议，因为必须捕获燃烧室气室的声学四分之一波模式与射流的相互作用。分析了这些四分之一波模式与流的相互作用，并比较了全燃烧器-增压计算与简化的燃烧器计算（忽略增压噪声）对火焰放热波动的声学响应。由于增压通风系统的激励，