Effects of Intrinsic Flame Instabilities on Thermoacoustic Oscillations in Lean Premixed Gas Turbines

Li, Fangyan; Tian, Xiaotao; Du, Mingyue; Shi, Lei; Cui, Jiashan

doi:10.1115/1.4053421

Cited by 2 publications

(1 citation statement)

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“…Thanks to its high computational accuracy and computational efficiency, the combination of RANS and Helmholtz solver is considered as a promising method for predicting thermoacoustic oscillations. However, the current methods of numerical analysis either analyze the coupling effect of the overall physical field [12][13][14] or decouple the flame dynamics or acoustic phenomena in the physical field alone, [15][16][17] and the numerical analysis of oscillations under the coupling effect between fluid dynamics, flame dynamics, and chemical reactions needs to be further explored. Meng et al 18 proposed a method coupling the RANS and linearized Navier-Stokes equations (LNSEs), aiming at predicting the acoustic damping effects with real geometry and different bias flow velocities.…”

Section: Introductionmentioning

confidence: 99%

Analysis of separating acoustics from the thermoacoustic system of methane combustion based on Reynolds-averaged Navier-Stokes and linearized Navier-Stokes equations

Shen

Liu

2023

Journal of Low Frequency Noise, Vibration and Active Control

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A model coupling Reynolds-averaged Navier-Stokes (RANS) method and linearized Navier-Stokes equations (LNSEs) was established in order to investigate the acoustic excitation and attenuation effect from a coupling perspective of time–space–frequency under various flow velocities and mass fractions of methane. Results show that the energy distribution of acoustic modes under high-frequency acoustic excitation is more uniform. The amplitude of the acoustic oscillation at a multiple coupling physical field is 10,000 times higher than that at simple flow field. The case when [Formula: see text] = 0.8 owns the largest percentage of energy conversion from fundamental to high-frequency signals, the largest percentage of transmitted waves from the combustion chamber system to outside and the strongest non-linear effect. When [Formula: see text] rises, the amplitude of oscillations at points and the attenuation effect of high-frequency signals along the axial are enhanced. At the case of Uin = 15 m/s, the amplitude of harmonics is reduced by 18% compared with other cases, while the proportion of the high-frequency harmonic increases, proving the non-linearity cannot be neglected in this case. As velocity rises, the energy conversion from fundamental to high-frequency signals enhances; while closer to the outlet position, the more complex the oscillation signal is. Model-shapes analysis shows that a case of [Formula: see text] = 0.8 owns the largest amplitude of the second harmonic at downstream of the burner, while the amplitude of the harmonics rapidly increases at Uin = 15 m/s at the end of the burner, which further indicates that the energy conversion of low-frequency signals to high-frequency signals occurs mainly in the middle and downstream regions.

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