Background Noise Effects on Combustor Stability
Background Noise Effects on Combustor Stability
复制标题
背景噪声对燃烧器稳定性的影响
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
A. Banaszuk
中科院分区：
文献类型：
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作者：
T. Lieuwen;A. Banaszuk
本文研究了背景湍流脉动对燃烧室稳定边界的影响。固有的湍流脉动作为附加的和参数的激励源，在燃烧室中的声波。虽然附加噪声源主要对燃烧室振荡产生定量影响，但参数噪声源可对其动态特性产生定性影响;这里特别感兴趣的是它们使在没有这些噪声源的情况下稳定的系统不稳定的能力。这些参数噪声源的重要性随着背景噪声水平的增加而增加，因此，在现实的、高雷诺数的系统中，比在简化的、实验室规模的燃烧室上进行的实验可能建议的作用更大。本文的目的是确定这些影响是否和/或何时可能是显着的。分析考虑了阻尼率、频率和燃烧响应波动的影响。结果表明，噪声阻尼和频率对燃烧室稳定性极限的影响相对较小，至少对于这里估计的波动强度而言是这样。噪声燃烧响应的影响，特别是流动和放热扰动之间的波动时间延迟的影响，可能是相当显著的，然而，在某些情况下，湍流强度低至μ/μ 5 - 10%。这些结果表明，确定性稳定性模型校准低湍流强度，实验室规模的燃烧室可能不足以描述现实的，高湍流燃烧室的稳定性限制。
This paper considers the effects of background turbulent fluctuations upon a combustor’s stability boundaries. Inherent turbulent fluctuations act as both additive and parametric excitation sources to acoustic waves in combustors. Although additive noise sources exert primarily quantitative effects upon combustor oscillations, parametric noise sources can exert qualitative impacts upon its dynamics; particularly of interest here is their ability to destabilize a system that is stable in the absence of these noise sources. The significance of these parametric noise sources increases with increased background noise levels and, thus, can play more of a role in realistic, highReynolds-number systems than experiments on simplified, lab-scale combustors might suggest. The objective of this paper is to determine whether and/or when these effects might be significant. The analysis considers the effects of fluctuations in damping rate, frequency, and combustion response. It is found that the effects of noisy damping and frequency upon the combustor’s stability limits is relatively small, at least for the fluctuation intensities estimated here. The effects of a noisy combustion response, particularly of a fluctuating time delay between flow and heat-release perturbations, can be quite significant, however, in some cases for turbulence intensities as low as u � /¯ ∼ 5‐10%. These results suggest that deterministic stability models calibrated on low turbulence intensity, lab-scale combustors might not adequately describe the stability limits of realistic, highly turbulent combustors.