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Identification of Combustion Noise and Flame Dynamics of Confined Turbulent Flames

受限湍流火焰的燃烧噪声和火焰动力学识别

基本信息

批准号：
259171976
负责人：
Professor Wolfgang Polifke, Ph.D.
金额：
--
依托单位：
Lehrstuhl für Thermofluiddynamik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/259171976?language=en
关键词：
Identification Combustion Noise Flame Dynamics

项目摘要

Combustion noise is an undesirable by-product of combusion processes, generated by unsteady heat release rate of the flame. For confined turbulent flames, two contributions can be distinguished: On the one hand, turbulent fluctuations of velocity or fuel concentration generate as a source term broad-band fluctuations of the heat release. On the other hand, the flame may be disturbed by acoustic waves impinging upon the flame. This acoustic-flame interaction is generally described by the flame transfer function (FTF) of the system, or by the corresponding scattering matrix. In general it is not possible to determine accurately the source terms without knowledge of the flame dynamics (as expressed in terms of the scattering matrix or the FTF), and vice versa. Furthermore, the sound pressure levels in a combustion chamber are determined not only by the noise sources, but also the flame dynamics. Thus comprehensive thermo-acoustic characterization of confined, turbulent flames requires to determine both the combustion noise source as well as the scattering matrix or FTF. The overall objective of the proposed project is to develop methods that allow the concurrent determination of the combustion noise source and the flame dynamics by combining advanced system identification (ASI) techniques with experiment or large eddy simulation. The main idea consists in modelling both flame dynamics and combustion noise by a polynomial approach based on the Box-Jenkins structure. This model may be considered as an extension of Finite Impulse Response (FIR) methods. This will make possible to predict combustion noise of confined, turbulent flames even in situations where acoustic-flame interactions are important -- a case that cannot be handled well by existing methods. Furthermore, ASI will increase the accuracy and robustness of FTF or scattering matrix identification in situations where combustion noise levels are high.

燃烧噪声是燃烧过程的不期望的副产品，由火焰的不稳定的热释放速率产生。对于受限湍流火焰，可以区分两种贡献：一方面，速度或燃料浓度的湍流波动作为源项产生放热的宽带波动。另一方面，火焰可能被撞击在火焰上的声波扰动。这种声-火焰相互作用通常由系统的火焰传递函数（FTF）或相应的散射矩阵来描述。一般来说，不可能在不知道火焰动力学（如用散射矩阵或FTF表示的）的情况下准确地确定源项，反之亦然。此外，燃烧室中的声压级不仅由噪声源决定，而且还由火焰动力学决定。因此，全面的热声特性的限制，湍流火焰需要确定燃烧噪声源以及散射矩阵或FTF。拟议项目的总体目标是开发的方法，允许同时确定的燃烧噪声源和火焰动力学相结合的先进系统识别（ASI）技术与实验或大涡模拟。的主要思想包括在建模火焰动力学和燃烧噪声的多项式方法的基础上的Box-Jenkins结构。该模型可以被认为是有限脉冲响应（FIR）方法的扩展。这将使得有可能预测燃烧噪声的限制，湍流火焰，即使在声火焰相互作用是重要的情况下，不能很好地处理现有的方法。此外，在燃烧噪声水平较高的情况下，ASI将提高FTF或散射矩阵识别的准确性和鲁棒性。