Investigation on flame characteristics of industrial gas turbine combustor with different mixing uniformities

The combustion characteristics for a gas turbine (GT) model combustor in air-inlet excitation are studied by Large Eddy Simulation (LES). Time series of heat release rate (HRR) fluctuation is captured during simulation. The precessing vortex core (PVC) structure is shown by pressure iso-surface, and the single/double helix branches of PVC alternately evolve in one forcing cycle. With the rotation of PVC, the high-speed ring zone (HSRZ) is periodically squeezed, and large-scale vortex roll-up results from that. The flame root structure is also significantly affected by PVC, which is one of the reasons for the HRR fluctuation. With the increase of the forcing amplitude, the flame response is divided into three parts. The linear growth zone and secondary rising zone are separated by saturation plateau. The flame dynamics analysis shows that the change of the flame structures and flame front oscillation modes are the apparent mechanism of the nonlinear flame response appearance.

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“…The FGM model performs the flamelet with the mixture fraction Z and the reaction progress variable C. 36,37 The Z and C are defined as follows:…”

Section: Numerical Approachesmentioning

confidence: 99%

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

Zhang

Liu

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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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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“…Zhao et al [15] built an experimental platform to research the important role of fuel flow and equivalent volume ratio in generating non-linear thermoacoustic instabilities in swirl combustion chambers. Zhang et al [16] investigated the effect of fuel mixture uniformity on the dynamic response of the flame. The study proved that the fuel/air mixture uniformity should be strictly controlled during the design of the combustion chamber to make the combustion chamber work safely and efficiently.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of a Two-Stage Swirl Burner

Lin

Zhang

et al. 2022

Energies

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In this study, we developed the design process and optimization of structural parameters of a new low-NOx burner based on low-NOx combustion technology and the flame stabilization principle. Firstly, on the basis of the two-stage swirl burner, we applied the fuel-graded combustion technology and introduced the central nozzle structure to explore the influence law of graded combustion on NOx emissions. Secondly, on the previously optimized structure, the matching law between the first- and second-stage cyclone blades is analyzed to obtain the optimum structural design solution for heat exchange efficiency and flame front length. Finally, a new conical blunt structure is introduced in conjunction with the flame stabilization principle, and we discuss the effects of different half cone angles on the flame stabilization, flame front length, and heat exchange efficiency of the burner. The research in this paper provides a reliable direction for the design optimization of low-NOx burners.

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Investigation on flame characteristics of industrial gas turbine combustor with different mixing uniformities

Cited by 16 publications

References 29 publications

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

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

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

Experimental and Numerical Study of a Two-Stage Swirl Burner

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