Nonlinear dynamics of a self-excited thermoacoustic system subjected to acoustic forcing
Nonlinear dynamics of a self-excited thermoacoustic system subjected to acoustic forcing
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DOI：
10.1016/j.proci.2014.05.029
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发表时间：
2015-01-01
影响因子：
3.4
通讯作者：
Hochgreb, Simone
中科院分区：
文献类型：
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作者：
Balusamy, Saravanan;Li, Larry K. B.;Hochgreb, Simone
我们通过实验研究了受声力作用的自激热声系统的非线性动力学。我们的目标是将这些动力学与受外力作用的通用模型振荡器的行为联系起来。正在研究的自激系统由封闭在带有开放式出口的石英管中的涡流稳定湍流预混火焰（当量比为 0.8，热功率为 13.6 kW）组成。我们以不同的振幅和频率对该系统施加声学作用，并使用压力传感器和火焰中的 OH* 化学发光来测量其响应。通过使用功率谱密度和庞加莱图分析数据，我们发现了一系列非线性动力学，包括（i）随着强迫幅度的增加，自激频率朝向或远离强迫频率的移动； (ii) 伴随的从周期性到双频准周期性的转变； (iii) 自激幅度的最终抑制，表明自激模式与强制模式的同步。通过进一步使用希尔伯特变换分析数据，我们发现了相位捕获的证据，这是一种以频率锁定而不锁相为特征的部分同步状态。所有这些动态都可以在受到外力作用的通用模型振荡器中找到。这表明这种振荡器可用于准确地表示受到类似强迫的热声自激燃烧系统。它还表明，此类振荡器的解析解可用于指导从真实热声系统获得的实验或数值数据的简化和分析，并确定对其动力学进行开环控制的有效方法。 (C) 2014 年作者。由爱思唯尔公司代表燃烧研究所出版。
We experimentally study the nonlinear dynamics of a self-excited thermoacoustic system subjected to acoustic forcing. Our aim is to relate these dynamics to the behavior of universal model oscillators subjected to external forcing.The self-excited system under study consists of a swirl-stabilized turbulent premixed flame (equivalence ratio of 0.8 and thermal power of 13.6 kW) enclosed in a quartz tube with an open-ended exit. We acoustically force this system at different amplitudes and frequencies, and measure its response with pressure transducers and OH* chemiluminescence from the flame. By analyzing the data with the power spectral density and the Poincare map, we find a range of nonlinear dynamics, including (i) a shifting of the self-excited frequency towards or away from the forcing frequency as the forcing amplitude increases; (ii) an accompanying transition from periodicity to two-frequency quasiperiodicity; and (iii) an eventual suppression of the self-excited amplitude, indicating synchronization of the self-excited mode with the forced mode. By further analyzing the data with the Hilbert transform, we find evidence of phase trapping, a partially synchronous state characterized by frequency locking without phase locking.All of these dynamics can be found in universal model oscillators subjected to external forcing. This suggests that such oscillators can be used to accurately represent thermoacoustically self-excited combusting systems subjected to similar forcing. It also suggests that the analytical solutions to such oscillators can be used to guide the reduction and analysis of experimental or numerical data obtained from real thermoacoustic systems, and to identify effective methods for open-loop control of their dynamics. (C) 2014 The Authors. Published by Elsevier Inc. on behalf of The Combustion Institute.