Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Zhang, Zhihao; Liu, Xiao; Zheng, Hongtao; Lv, Guangpu; Li, Shengnan

doi:10.1177/09576509221099388

Cited by 3 publications

(1 citation statement)

References 38 publications

(47 reference statements)

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“…The predicted oscillation was found to be sustained by a longitudinal thermo-acoustic mode at a frequency of about 209 Hz, closely matching the experimentally measured value. Zhang et al 46,47 recently utilised a similar LES methodology including artificial forcing of the inflow velocity. The combustor’s flame dynamics were analysed, although no direct comparison against the experimental data was presented for the reacting flow field.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal and azimuthal thermo-acoustic instabilities in an industrial gas turbine combustor operating at elevated pressure

Fredrich,

Jones,

Marquis

et al. 2023

International Journal of Spray and Combustion Dynamics

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This work numerically investigates longitudinal and azimuthal thermo-acoustic instabilities in the swirl-stabilised can-type industrial SGT-100 gas turbine combustor operated at elevated pressures of 3 and 6 bar. Previous experiments have shown that the combustor is susceptible to self-excited flame oscillations sustained by a thermo-acoustic feedback loop at specific operating conditions. In order to gain a better understanding of this feedback loop, a fully compressible large eddy simulation method is applied. The unknown sub-grid scale turbulence-chemistry interactions are modelled via a transported probability density function approach solved by the Eulerian stochastic fields method. First, the reaction zones and global flame topology at both operating pressures are analysed and compared to experimental images providing good qualitative agreement. Radial profiles of time-averaged and root-mean-square quantities furthermore demonstrate good quantitative agreement with the available measurement data. The applied simulation approach is capable of successfully reproducing self-excited thermo-acoustic instabilities in the longitudinal direction. The fundamental frequency of the predicted limit-cycle oscillation matches the experimentally measured frequency with high accuracy. Similar to the experimental observations, the fluctuation amplitudes of the pressure and global heat release rate increase significantly upon increasing the mean operating pressure from 3 to 6 bar. In addition to the dominant longitudinal mode, a high-frequency, low-amplitude azimuthal mode is also identified at both pressures. This azimuthal mode is periodically amplified and attenuated by the superposed longitudinal mode and induces small asymmetric (around the burner circumference) fluctuations of the local fuel and total mixture mass flow rates entering the flame region.

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Section: Introductionmentioning

confidence: 99%

Longitudinal and azimuthal thermo-acoustic instabilities in an industrial gas turbine combustor operating at elevated pressure

Fredrich,

Jones,

Marquis

et al. 2023

International Journal of Spray and Combustion Dynamics

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Large eddy simulations of pilot-stage equivalence ratio effects on combustion instabilities in a coaxial staged model combustor

Lv,

Liu,

Zhang

et al. 2023

Physics of Fluids

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In this paper, the effects of pilot-stage equivalence ratio on combustion instabilities in a coaxial staged model combustor are investigated using the Wall-Modeled Large Eddy Simulation. The global equivalence ratio is maintained constant, and the Stratification Ratio of the first main-stage and the second main-stage is set to 1; the dynamic mode decomposition and system identification methods are employed to analyze the flame dynamics, velocity, heat release rate modes, and flame transfer function (FTF) of the model combustor under different pilot-stage equivalence ratios. The results show that when the pilot-stage equivalence ratio is 0.6, the oscillation amplitude of heat release rate (HRR) exceeds 7.5% of the global average HRR, and the velocity oscillation and the global HRR oscillation in the combustor are coupled. As the pilot-stage equivalence ratio increases to 0.8, the oscillation amplitude of HRR decreases to 2.5%, and the oscillation of velocity and global HRR in the combustor are decoupled. Furthermore, the maximum value of FTF decreases from 3.5 to below 1 with the increase in the pilot-stage equivalence ratio.

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The self-excited thermoacoustic instability behavior of a premixed hedge combustor with an elbow-connection or T-shape supply system

Du,

Zhang,

Zhang

et al. 2024

Proceedings of the Institution of Mechanical Engineers, Part A:

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The self-excited thermoacoustic instability (SETAI) frequently occurs in combustion equipment, leading to intense mechanical vibration, big noise and flame instability. SETAI poses a substantial challenge to the advancement of combustion technology, chiefly due to its complex mechanism. Our previous research has demonstrated that altering the premixed chamber length upstream of furnace can impact the interaction between heat release and sound pressure oscillations, which potentially enables SETAI control. However, supply duct is generally not straight, and changing the premixed section is impractical and unsafe. This paper aims to investigate the influence of introducing elbows and adjusting the supply duct length preceding the premixing stage on SETAI behavior. The goal is to offer guidance for the safe and convenient control of SETAI. Finds reveal that incorporating an elbow in the premixed chamber or changing its position does not affect sound wave propagation along the duct’s center axis within a low frequency regime when maintaining a constant total equivalent length. In systems with both separate and premixed sections, the oscillation pattern is determined by the total time required for acoustic propagation throughout the entire supply system. Consequently, modifications to either of these lengths can impact SETAI.

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Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Cited by 3 publications

References 38 publications

Longitudinal and azimuthal thermo-acoustic instabilities in an industrial gas turbine combustor operating at elevated pressure

Longitudinal and azimuthal thermo-acoustic instabilities in an industrial gas turbine combustor operating at elevated pressure

Large eddy simulations of pilot-stage equivalence ratio effects on combustion instabilities in a coaxial staged model combustor

The self-excited thermoacoustic instability behavior of a premixed hedge combustor with an elbow-connection or T-shape supply system

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