Effect of Flame Structure on the Flame Transfer Function in a Premixed Gas Turbine Combustor
Effect of Flame Structure on the Flame Transfer Function in a Premixed Gas Turbine Combustor
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DOI：
10.1115/gt2008-51014
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发表时间：
2010-02
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影响因子：
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通讯作者：
Daesik Kim;J. Lee;B. Quay;D. Santavicca;Kwanwoo Kim;S. Srinivasan
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文献类型：
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作者：
Daesik Kim;J. Lee;B. Quay;D. Santavicca;Kwanwoo Kim;S. Srinivasan
对预混燃气轮机燃烧室的火焰传递函数进行了实验测定。燃料(天然气)在燃烧室堵塞的入口处上游预混空气。因此，火焰传递函数的输入是没有当量比波动的燃料/空气混合物的附加速度波动。入口速度波动通过变速警报器在75-280赫兹的强迫频率上实现，并在燃烧室的入口处使用热线风速计测量。通过对整个火焰的化学发光测量，确定了输出函数(热释放)。记录了火焰图像，以了解火焰结构如何在火焰对入口速度扰动的全局放热响应中发挥作用。结果表明，火焰传递函数的增益和相位依赖于火焰的结构以及入口速度调制的频率和幅度，并且可以用火焰的相对长度尺度概括为入口速度扰动的对流长度尺度，该尺度由Strouhal数表示。非线性火焰响应表现为周期性的旋涡从剪切层脱落，并且随着调制频率的增加，入口速度脉动值较小时出现非线性。然而，对于给定的调制频率，火焰结构并不影响开始非线性的入口速度波动的大小。版权所有©2008，ASME
The flame transfer function in a premixed gas turbine combustor is experimentally determined. The fuel (natural gas) is premixed with air upstream of a choked inlet to combustor. Therefore, the input to the flame transfer function is the imposed velocity fluctuations of the fuel/air mixture without equivalence ratio fluctuations. The inlet-velocity fluctuations are achieved by a variable-speed siren over the forcing frequency of 75–280 Hz and measured using a hot-wire-anemometer at the inlet to the combustor. The output function (heat release) is determined using chemiluminescence measurement from the whole flame. Flame images are recorded to understand how the flame structure plays a role in the global heat release response of flame to the inlet-velocity perturbation. The results show that the gain and phase of the flame transfer function depend on flame structure as well as the frequency and magnitude of inlet-velocity modulation and can be generalized in terms of the relative length scale of flame to convection length scale of inlet-velocity perturbation, which is represented by a Strouhal number. Non-linear flame response is characterized by a periodic vortex shedding from shear layer and the non-linearity occurs at lower magnitude of inlet-velocity fluctuation as the modulation frequency increases. However, for a given modulation frequency, the flame structure does not affect the magnitude of inlet-velocity fluctuation at which the non-linearity starts.Copyright © 2008 by ASME