THERMAL SCIENCE

International Scientific Journal

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Experimental investigations on acoustic-velocity-flame dynamic characteristics of a stratified burner

ABSTRACT
To reveal the influence of interaction between pilot and main flames on flow and thermo-acoustic instability characteristics, high-frequency measurement devices such as High-Frequency Particle Image Velocimetry (HFPIV), high-speed camera, pressure sensors, and photomultiplier tube were applied to study the acoustic-velocity-flame dynamic characteristics of the stratified burner under ambient temperature and pressure. Results show that the pilot swirling flow significantly influences the acoustic-velocity-flame dynamic characteristics of the stratified burner. When the pilot and main stage are operated with a swirling air jet and swirling flame, the main recirculation zone disappears, the thermo-acoustic instability is strengthened and the frequency of thermo-acoustic instability is locked with the large-scale vortex shedding frequency. When the pilot stage is converted into a swirling flame, the main recirculation zone re-appears down stream of the nozzle outlet, and the high-temperature burned gas is rolled back to improve the combustion stability of the swirling flame. However, in this case, the interaction between the pilot and main flames makes the thermo-acoustic instability frequency not well consistent with large-scale vortex shedding frequency. The interaction between the main stage and pilot stage flames leads to the increase of the flame angle of the main stage. The heat release fluctuation at the flame interaction region is the most intense, and the large-scale vortex in the outer shear layer of the main stage also causes the flame to produce severe oscillation.
KEYWORDS
PAPER SUBMITTED: 2023-11-20
PAPER REVISED: 2024-03-20
PAPER ACCEPTED: 2024-03-24
PUBLISHED ONLINE: 2024-11-09
DOI REFERENCE: https://doi.org/10.2298/TSCI231120235J
REFERENCES
  1. Han X, et al. Flame interactions in a stratified swirl burner: flame stabilization, combustion instabilities and beating oscillation [J]. Combustion and Flame, 2020, 212: 500-509
  2. Mongia H C, et al. Challenges and progress in controlling dynamics in gas turbine combustors [J]. Journal of Engineering for Gas Turbines and Power, 2003, 19: 822-829
  3. Zhang C, et al. Experimental investigations on central vortex core in swirl spray flames using high-speed laser diagnostics[J]. Physics of Fluids, 2023, 35: 035130
  4. Yan B, et al. Simultaneous visualization of instantaneous unburnt and preheating zones in turbulent premixed flames under transverse acoustic excitations[J]. Physics of Fluids, 2022, 34: 095107
  5. Zhang B, et al. Contributions of hydrodynamic features of a swirling flow to thermoacoustic instabilities in a lean premixed swirl stabilized combustor[J]. Physics of Fluids, 2019, 31: 075106
  6. Wang G F, et al. Flame propagation patterns and local flame features of an annular combustor with multiple centrally staged swirling burners[J]. Physics of Fluids, 2023, 35: 085134
  7. Menon S. Acoustic-vortex-flame interactions in gas turbines [J]. Progress in Astronautics and Aeronautics, 2005, 210: 277
  8. Balachandran R, et al. Experimental investigation of the nonlinear response of turbulent premixed flames to imposed inlet velocity oscillations [J]. Combustion and Flame, 2005, 143(1-2): 37-55
  9. Bellows B D, et al. Flame transfer function saturation mechanisms in a swirl-stabilized combustor [J]. Proceedings of the Combustion Institute, 2007, 31(2): 3181-3188
  10. Santosh H, et al. Premixed flame response to equivalence ratio perturbations [J]. Combustion Theory and Modelling, 2010, 14(5): 681-714
  11. Bellows B D, et al. Nonlinear flame transfer function characteristics in a swirl-stabilized Combustor [J]. Journal of Engineering for Gas Turbines and Power, 2007, 129(4): 954-961
  12. Thumuluru S K, et al. Characterization of acoustically forced swirl flame dynamics [J]. Proceedings of the Combustion Institute, 2009, 32(2): 2893-2900
  13. Schimek S, et al. An experimental investigation of the nonlinear response of an atmospheric swirl-stabilized premixed flame [J]. Journal of Engineering for Gas Turbines and Power, 2011, 133(10): 101502
  14. Schimek S, et al. Amplitude-dependent flow field and flame response to axial and tangential velocity fluctuations [J]. Journal of Engineering for Gas Turbines and Power, 2015, 137(8): 081501
  15. Terhaar S, et al. Impact of shear flow instabilities on the magnitude and saturation of the flame response [J]. Journal of Engineering for Gas Turbines and Power, 2014, 136(7): 071502
  16. Oberleithner K, et al. Shear flow instabilities in swirl-stabilized combustors and their impact on the amplitude dependent flame response: a linear stability analysis [J]. Combustion and Flame, 2015, 162(1): 86-99
  17. Palies P, et al. Experimental study on the effect of swirler geometry and swirl number on flame describing functions [J]. Combustion Science and Technology, 2011, 183(7): 704-717
  18. Palies P, et al. The combined dynamics of swirler and turbulent premixed swirling flames [J]. Combustion and Flame, 2010, 157(9): 1698-1717
  19. Terhaar S, et al. Combustion and flame suppression and excitation of the precessing vortex core by acoustic velocity fluctuations: an experimental and analytical study [J]. Combustion and Flame, 2016, 172: 234-251
  20. Ma J L, et al. Influence of the co- and counter-swirl on combustion instability of the centrally staged combustor[J]. Physics of Fluids, 2023, 35: 087127
  21. Chong C T, et al. Effect of mixture flow stratification on premixed flame structure and emissions under counter-rotating swirl burner configuration [J]. Applied Thermal Engineering, 2016, 105: 905-912
  22. Kim K T, et al. The nonlinear heat release response of stratified lean-premixed flames to acoustic velocity oscillations[J]. Combustion and Flame. 2011, 158: 2482-2499
  23. Han X, et al. Flame macrostructures and thermoacoustic instabilities in stratified swirling flames [C] //Proceedings of the Combustion Institute, 2019, 37: 5377-5384
  24. Lv G P, et al. Large eddy simulations of pilot-stage equivalence ratio effects on combustion instabilities in a coaxial staged model combustor[J]. Physics of Fluids, 2023, 35: 095134
  25. Weber R, et al. Combustion accelerated swirling flows in high confinements. Prog. Energy Combust. Sci. 1992; 18 :349–67
  26. Procacci A, et al. Multi-scale proper orthogonal decomposition analysis of instabilities in swirled and stratified flames[J]. Physics of Fluids, 2022, 34: 124103
  27. Krasilnikov V A, et al. Atmospheric turbulence and radio-wave propagation [J]. Monograph on Radio-wave Propagation in the Troposphere, 1962, 62: 145
  28. Sirovich L. Turbulence and the dynamics of coherent structures. I-coherent structures [J]. Quarterly of Applied Mathematics, 1987, 45(3): 561-571
  29. Wyatt C, et al. The effect of variable fuel staging transients on self-excited instabilities in a multiple-nozzle combustor[J]. Combustion and Flame, 2018, 194: 472-484
  30. Richards G A, et al. Characterization of oscillations during premix gas turbine combustion[J]. Journal of Engineering for Gas Turbines and Power, 1998, 120(2): 294-302
  31. MENON S. Acoustic-vortex-flame interactions in gas tur-bines[J]. Progress in Astronautics and Aeronautics, 2005, 210: 277
  32. Li J X, et al. Open-Source combus-tion instability low order simulator (OSCILOS–Long). Technical report, 2017
  33. Liu W J, et al. Dynamic Response of Stratified Flames to Acoustic Excitation in a Multi-Swirler Model Combustor [C] // Proceedings of the ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. Volume 3B: Combustion, Fuels, and Emissions. Rotterdam, Netherlands. June 13–17, 2022. V03BT04A035. ASME