Imaging-based harmonic frequency analysis of a bluff-body premixed flame under acoustic excitations
Imaging-based harmonic frequency analysis of a bluff-body premixed flame under acoustic excitations
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DOI：
10.1016/j.ast.2021.107254
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发表时间：
2021-12
影响因子：
5.6
通讯作者：
Qian Wang;Jiangtao Wang;Xiaohan Mei;Yong-chao Sun;Mingbo Sun;Jiajian Zhu;C.Y. Zhao
中科院分区：
文献类型：
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作者：
Qian Wang;Jiangtao Wang;Xiaohan Mei;Yong-chao Sun;Mingbo Sun;Jiajian Zhu;C.Y. Zhao
采用高速彩色和纹影成像技术研究了声激励下崖体预混甲烷火焰的动态响应。测试和分析了两种不同幅值的激励频率（50 Hz-105、110、115 dB和200 Hz-120、125、130 dB）。快速傅里叶变换（FFT）分析揭示了主导激励频率，以及几个谐波频率作为非线性响应。利用时间分辨彩色图像和纹影图像进行动态模态分解（DMD）分析，提取主频和倍频的空间模式。结果表明：在这些频率下，能量分布对喷嘴轴呈轴对称分布，正能带和负能带交替出现；在不同的激励频率和幅值下，其空间分布有很大的差异。从彩色和纹影图像的DMD结果中观察到倍增频率下的能带细分现象。
The dynamic responses of a bluff-body premixed methane flame under acoustic excitations were studied using high speed color and schlieren imaging techniques. Two excitation frequencies at different amplitudes were tested and analyzed (50 Hz-105, 110, 115 dB and 200 Hz-120, 125, 130 dB). The fast Fourier transform (FFT) analysis reveals the dominant excitation frequency, as well as several harmonic frequencies as nonlinear responses. The dynamic mode decomposition (DMD) analysis was conducted using the time-resolved color and schlieren images to extract the spatial pattern at the dominant and multiplication harmonic frequencies. The results indicate that under these frequencies, the energy distribution has exhibited axisymmetric patterns to the nozzle axis, with positive and negative energy bands appearing alternatively. The spatial distribution has shown great variances under different excitation frequencies and amplitudes. An energy band sub-dividing phenomenon at multiplication frequencies was observed from the DMD results of both color and schlieren images.