Acoustic Perturbation Equations for Reacting Flows to Compute Combustion Noise
Acoustic Perturbation Equations for Reacting Flows to Compute Combustion Noise
复制标题
用于计算燃烧噪声的反应流的声学扰动方程
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
M. Meinke
中科院分区：
文献类型：
--
作者：
T. Bui;W. Schröder;M. Meinke
推导了反应流动的声学微扰方程(APE-RF)，并结合混合方法研究了燃烧噪声。该方法在第一步使用大涡模拟(LES)数据，在第二步使用APE-RF系统。新推出的APE-RF系统在右侧包含几个源项(RHS)。就它们与各种健全机制的关系进行了详细的讨论。声源包括非定常放热、非等摩尔燃烧、组分扩散、热扩散、粘性效应、非均匀流动和非恒定燃烧压力效应以及密度不均匀加速的影响。结果表明，非定常放热发生在大涡模拟可立即获得的密度的总时间导数中。通过混合方法计算仅由密度的实质性导数产生的开放湍流非预混火焰的声场，该密度除包含非定常热释放外，还包括非等摩尔燃烧、热和组分扩散的影响以及粘性效应，即忽略剩余项。通过将数值数据与实验结果进行比较，表明在较宽的频率范围内，密度的总时间导数包含了反应流动中的主要声源。然而，也指出，为了在整个频率范围内模拟所有细节，在分析中将考虑APE-RF系统的RHS上发生的剩余源机制。
Acoustic perturbation equations for reacting flows (APE-RF) are derived to investigate combustion noise in conjunction with a hybrid approach. The method uses large-eddy simulation (LES) data in the first step and the APE-RF system in the second step. The newly derived APE-RF system contains several source terms on the right-hand side (RHS). They are discussed in detail with respect to their relation to various sound mechanisms. The acoustic sources contain the impact of unsteady heat release, non-isomolar combustion, species diffusion, heat diffusion, viscous effects, non-uniform mean flow and non-constant combustion pressure effects, and the influence of acceleration of density inhomogeneities. It is shown that the unsteady heat release occurs in the total time derivative of the density that is immediately available from an LES. By computing via the hybrid method the sound field of an open turbulent non-premixed flame being generated just by the substantial derivative of the density, which contains besides the unsteady heat release, the effect of non-isomolar combustion, heat and species diffusion, and viscous effects, i.e., the remaining terms are neglected, and by comparing the numerical data with experimental findings the total temporal derivative of the density is shown to contain for a wide frequency range the major sound sources in reacting flows. However, it is also indicated that to simulate all the details in the complete frequency range the remaining source mechanisms occurring on the RHS of the APE-RF system are to be taken into account in the analysis.