Numerical results on noise-induced dynamics in the subthreshold regime for thermoacoustic systems
Numerical results on noise-induced dynamics in the subthreshold regime for thermoacoustic systems
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DOI：
10.1016/j.jsv.2016.12.004
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发表时间：
2017-03
影响因子：
4.7
通讯作者：
Vikrant Gupta;Aditya Saurabh;C. Paschereit;Lipika Kabiraj
中科院分区：
文献类型：
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作者：
Vikrant Gupta;Aditya Saurabh;C. Paschereit;Lipika Kabiraj
热声不稳定性是实际燃烧系统中的一个严重问题。这样的系统是固有的噪声，因此噪声对热声不稳定性的动态的影响是一个具有实际意义的方面。目前的工作是由最近的一份关于相干共振或噪声诱导的相干性的实验观察报告激发的，该相干共振或噪声诱导的相干性随着系统接近稳定裕度而对噪声强度具有类似共振的依赖性，用于原型预混层流火焰燃烧器（Kabiraj等人，E，4（2015））。我们数值研究代表性的热声模型，这样的噪声诱导动力学。类似的实验，我们研究系统动力学的变化，响应于噪声强度的变化，并在一个关键的控制参数的系统接近其稳定裕度。定性匹配确定的实验结果和观察在这里研究的代表性模型证实，相干共振是热声系统的一个功能。我们还将仅限于亚临界Hopf分岔的实验结果推广到了超临界Hopf分岔。我们发现，这种现象有质的差异，通过亚临界和超临界Hopf分岔过渡的系统。两个重要的实际影响与调查结果。首先，噪声诱导的相干性的增加，作为系统的方法的发病热声不稳定性可以被认为是一个前兆的不稳定性。其次，噪声诱导的动力学的分叉类型的依赖性，可以用来区分亚临界和超临界分叉之前的不稳定性发作。
Thermoacoustic instability is a serious issue in practical combustion systems. Such systems are inherently noisy, and hence the influence of noise on the dynamics of thermoacoustic instability is an aspect of practical importance. The present work is motivated by a recent report on the experimental observation of coherence resonance, or noise-induced coherence with a resonance-like dependence on the noise intensity as the system approaches the stability margin, for a prototypical premixed laminar flame combustor (Kabiraj et al., Phys. Rev. E, 4 (2015)). We numerically investigate representative thermoacoustic models for such noise-induced dynamics. Similar to the experiments, we study variation in system dynamics in response to variations in the noise intensity and in a critical control parameter as the systems approach their stability margins. The qualitative match identified between experimental results and observations in the representative models investigated here confirms that coherence resonance is a feature of thermoacoustic systems. We also extend the experimental results, which were limited to the case of subcritical Hopf bifurcation, to the case of supercritical Hopf bifurcation. We identify that the phenomenon has qualitative differences for the systems undergoing transition via subcritical and supercritical Hopf bifurcations. Two important practical implications are associated with the findings. Firstly, the increase in noise-induced coherence as the system approaches the onset of thermoacoustic instability can be considered as a precursor to the instability. Secondly, the dependence of noise-induced dynamics on the bifurcation type can be utilised to distinguish between subcritical and supercritical bifurcation prior to the onset of the instability.