Optical Transfer Function Measurements for Technically Premixed Flames
Optical Transfer Function Measurements for Technically Premixed Flames
复制标题
技术预混火焰的光学传递函数测量
DOI：
10.1115/gt2008-51500
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
W. Mohr
中科院分区：
文献类型：
--
作者：
B. Schuermans;F. Guethe;W. Mohr
本文提出了一种测量热声传递函数的新方法。这些传递函数对于预测燃气涡轮机燃烧系统的声学特性是必不可少的。热声预测已成为低NOx燃烧系统开发过程中必不可少的一步。所提出的方法在恶劣环境中特别有用。它利用不同物种的化学发光的同时测量，以便通过逆方法获得热释放波动。通常，放热波动有两个贡献：一个是由于当量比波动，另一个是由于进入反应区的混合物的质量流量的调制。由于一个单一物种的化学发光取决于不同的两个贡献，这是不可能的定量估计的热量的基础上，这一信息。基于纯声学方法的传递矩阵的测量提供了定量结果，与相互作用机制的性质无关。然而，这种方法很难应用于工业全尺寸实验。在这项工作中开发的方法使用几个物种的化学发光时间痕迹。校准后，超定逆方法被用来计算两个热释放贡献的时间轨迹。这里提出的光学方法的优点是，它不仅提供定量的热释放波动，但它也量化的基本物理机制，导致热释放波动：它显示了什么部分的热释放是由当量比波动和什么部分由火焰前锋动态。该方法已在全尺寸旋流稳定燃气涡轮机燃烧器上进行了试验。与纯声学方法的比较验证了这一概念。版权所有© 2008阿尔斯通
This paper deals with a novel approach for measuring thermo-acoustic transfer functions. These transfer functions are essential to predict the acoustic behavior of gas turbine combustion systems. Thermoacoustic prediction has become an essential step in the development process of low-NOx combustion systems. The proposed method is particularly useful in harsh environments. It makes use of simultaneous measurement of the chemiluminescence of different species in order to obtain the heat release fluctuations via an inverse method. Generally, the heat release fluctuation has two contributions: one due to equivalence ratio fluctuations, the other due to modulations of mass flow of mixture entering the reaction zone. Because the chemiluminescence of one single species depends differently on the two contributions, it is not possible to quantitatively estimate the heat based on this information. Measurement of the transfer matrix based on a purely acoustic method provides quantitative results, independent of the nature of the interaction mechanism. However, this method is difficult to apply in industrial full-scale experiments. The method developed in this work uses the chemiluminescence time traces of several species. After calibration, an over-determined inverse method is used to calculate the two heat release contributions from the time traces. The optical method proposed here has the advantage that it does not only provide quantitative heat release fluctuations, but it also quantifies the underlying physical mechanisms that cause the heat release fluctuations: it shows what part of the heat release is caused by equivalence ratio fluctuations and what part by flame front dynamics. The method has been tested on a full scale, swirl stabilized gas turbine burner. Comparison with a purely acoustic method validated the concept.Copyright © 2008 by Alstom