This paper presents the experimental investigation of pulsation-amplitude-dependent flame dynamics associated with transverse thermoacoustic oscillations at screech level frequencies in a generic gas turbine combustor. Specifically, the flame behavior at different levels of pulsation amplitudes is assessed and interpreted. Spatial dynamics of the flame are measured by imaging the OH chemiluminescence (CL) signal synchronously to the dynamic pressure at the combustor's face plate. First, linear thermoacoustic stability states, modal dynamics, and flame-acoustic phase relations are evaluated. It is found that the unstable acoustic modes converge into a predominantly rotating character in the direction of the mean flow swirl. Furthermore, the flame modulation is observed to be in phase with the acoustic pressure at all levels of the oscillation amplitude. Second, distributed flame dynamics are investigated by means of visualizing the mean and oscillating heat release distribution at different pulsation amplitudes. The observed flame dynamics are then compared against numerical evaluations of the respective amplitude-dependent thermoacoustic growth rates, which are computed using analytical models in the fashion of a noncompact flame-describing function. While results show a nonlinear contribution for the individual growth rates, the superposition of flame deformation and displacement balances out to a constant flame driving. This latter observation contradicts the state-of-the-art perception of root-causes for limit-cycle oscillations in thermoacoustic gas turbine systems, for which the heat release saturates with increasing amplitudes. Consequently, the systematic observations and analysis of amplitude-dependent flame modulation shows alternative paths to the explanation of mechanisms that might cause thermoacoustic saturation in high frequency systems.

References

References
1.
Schuermans
,
B.
,
Bothien
,
M.
,
Maurer
,
M.
, and
Bunkute
,
B.
,
2015
, “
Combined Acoustic Damping-Cooling System for Operational Flexibility of GT26/GT24 Reheat Combustors
,”
ASME
Paper No. GT2015-42287.
2.
O'Connor
,
J.
,
Acharya
,
V.
, and
Lieuwen
,
T.
,
2015
, “
Transverse Combustion Instabilities: Acoustic, Fluid-Mechanic, and Flame Processes
,”
Prog. Energy Combust. Sci.
,
49
, pp.
1
39
.
4.
Lieuwen
,
T.
,
2012
,
Unsteady Combustor Physics
,
Cambridge University Press
,
Cambridge, UK
.
5.
Schimek
,
S.
,
Cosic
,
B.
,
Moeck
,
J.
,
Terhaar
,
S.
, and
Paschereit
,
C.
,
2015
, “
Amplitude-Dependent Flow Field and Flame Response to Axial and Tangential Velocity Fluctuations
,”
ASME J. Eng. Gas Turbines Power
,
137
(
8
), p.
081501
.
6.
Berger
,
F.
,
Hummel
,
T.
,
Hertweck
,
M.
,
Kaufmann
,
J.
,
Schuermans
,
B.
, and
Sattelmayer
,
T.
,
2017
, “
High-Frequency Thermoacoustic Modulation Mechanisms in Swirl-Stabilized Gas Turbine Combustors—Part I: Experimental Investigation of Local Flame Response
,”
ASME J. Eng. Gas Turbines Power
,
139
(
7
), p. 071501.
7.
Hummel
,
T.
,
Berger
,
F.
,
Hertweck
,
M.
,
Schuermans
,
B.
, and
Sattelmayer
,
T.
,
2017
, “
High-Frequency Thermoacoustic Modulation Mechanisms in Swirl-Stabilized Gas Turbine Combustors—Part II: Modeling and Analysis
,”
ASME J. Eng. Gas Turbines Power
,
139
(
7
), p.
071502
.
8.
Rayleigh
,
J.
,
1896
,
The Theory of Sound
, 2nd ed., Vol. 1–2, MacMillan, London, pp. 224–234.
9.
Dowling
,
A. P.
,
1997
, “
Nonlinear Self-Excited Oscillations of a Ducted Flame
,”
J. Fluid Mech.
,
346
, pp.
271
290
.
10.
Bellows
,
B. D.
,
Bobba
,
M. K.
,
Seitzman
,
J. M.
, and
Lieuwen
,
T.
,
2007
, “
Nonlinear Flame Transfer Function Characteristics in a Swirl-Stabilized Combustor
,”
ASME J. Eng. Gas Turbines Power
,
129
(
4
), pp. 954–961.
11.
Bellows
,
B. D.
,
Bobba
,
M. K.
,
Forte
,
A.
,
Seitzman
,
J. M.
, and
Lieuwen
,
T.
,
2007
, “
Flame Transfer Function Saturation Mechanisms in a Swirl-Stabilized Combustor
,”
Proc. Combust. Inst.
,
31
(
2
), pp.
3181
3188
.
12.
Schuermans
,
B.
,
2003
, “
Modeling and Control of Thermoacoustic Instabilities
,”
Ph.D. thesis
, Ècole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.https://infoscience.epfl.ch/record/33275/files/EPFL_TH2800.pdf
13.
Wassmer
,
D.
,
Schuermans
,
B.
,
Paschereit
,
C. O.
, and
Moeck
,
J. P.
,
2016
, “
An Acoustic Time-of-Flight Approach for Unsteady Temperature Measurements: Characterization of Entropy Waves in a Model Gas Turbine Combustor
,”
ASME J. Eng. Gas Turbines Power
,
139
(
4
), p.
041501
.
14.
Berger
,
F.
,
Kaufmann
,
J.
,
Schuermans
,
B.
, and
Sattelmayer
,
T.
,
2017
, “
Identification of Flame Displacement From High-Frequency Thermoacoustic Pulsations in Gas Turbine Combustors
,”
24th International Congress on Sound and Vibration
(ICSV), July 23–27, London, Paper No.
878
.https://www.iiav.org/archives_icsv_last/2017_icsv24/content/papers/papers/full_paper_878_20170409194732793.pdf
15.
Hummel
,
T.
,
Hammer
,
K.
,
Romero
,
P.
,
Schuermans
,
B.
, and
Sattelmayer
,
T.
,
2017
, “
Low-Order Model of Nonlinear High-Frequency Transversal Thermoacoustic Oscillations in Gas Turbine Combustors
,”
ASME J. Eng. Gas Turbines Power
,
139
(
7
), p.
071503
.
16.
Sangl
,
J.
,
Mayer
,
C.
, and
Sattelmayer
,
T.
,
2011
, “
Dynamic Adaption of Aerodynamic Flame Stabilization of a Premix Swirl Burner to Fuel Reactivity Using Fuel Momentum
,”
ASME J. Eng. Gas Turbines Power
,
133
(
7
), p.
071501
.
17.
Mayer
,
C.
,
Sangl
,
J.
,
Sattelmayer
,
T.
,
Lachaux
,
T.
, and
Bernero
,
S.
,
2011
, “
Study on the Operational Window of a Swirl Stabilized Syngas Burner Under Atmospheric and High Pressure Conditions
,”
ASME J. Eng. Gas Turbines Power
,
134
(
3
), p. 031506.
18.
Lefebvre
,
A. H.
, and
Ballal
,
D. R.
,
1998
,
Gas Turbine Combustion
,
CRC Press
, Boca Raton, FL.
19.
Güthe
,
F.
, and
Schuermans
,
B.
,
2007
, “
Phase-Locking in Post-Processing for Pulsating Flames
,”
Meas. Sci. Technol.
,
18
(9), p. 3036.
20.
Moeck
,
J.
,
Bourgouin
,
J.-F.
,
Durox
,
D.
,
Schuller
,
T.
, and
Candel
,
S.
,
2013
, “
Tomographic Reconstruction of Heat Release Rate Perturbations Induced by Helical Modes in Turbulent Swirl Flames
,”
Exp. Fluids
,
54
, p.
1498
.
21.
Bourgouin
,
J.
,
Durox
,
D.
,
Moeck
,
J.
,
Schuller
,
T.
, and
Candel
,
S.
,
2013
, “
Self-Sustained Instabilities in an Annular Combustor Coupled by Azimutal and Longitudinal Acoustic Modes
,”
ASME
Paper No. GT2013-95010.
22.
Noiray
,
N.
, and
Schuermans
,
B.
,
2013
, “
On the Dynamic Nature of Azimuthal Thermoacoustic Modes in Annular Gas Turbine Combustion Chambers
,”
Proc. R. Soc. A
,
469
(
2151
), p. 20120535.
23.
Hummel
,
T.
,
Berger
,
F.
,
Schuermans
,
B.
, and
Sattelmayer
,
T.
,
2016
, “
Theory and Modeling of Non-Degenerate Transversal Thermoacoustic Limit Cycle Oscillations
,”
International Symposium on Thermoacoustic Instabilities in Gas Turbines and Rocket Engines
, Industry Meets Academia, Munich, Germany, May 30–June 2, Paper No.
GTRE-038
.https://www.researchgate.net/publication/304570822_Theory_and_Modeling_of_Non-Degenerate_Transversal_Thermoacoustic_Limit_Cycle_Oscillations
24.
Kim
,
K. T.
,
Lee
,
J. G.
,
Quay
,
B. D.
, and
Santavicca
,
D. A.
,
2011
, “
The Dynamic Response of Turbulent Dihedral V Flames: An Amplification Mechanism of Swirling Flames
,”
Combust. Sci. Technol.
,
183
(
2
), pp.
163
179
.
25.
Feldmann
,
M.
,
2011
, “
Hilbert Transform in Vibration Analysis
,”
Mech. Syst. Signal Process.
,
25
(
3
), pp.
735
802
.
You do not currently have access to this content.