The majority of recent stationary gas turbine combustors employ swirling flows for flame stabilization. The swirling flow undergoes vortex breakdown (VB) and exhibits a complex flow field including zones of recirculating fluid and regions of high shear intensities. Often, self-excited helical flow instabilities, which manifest in a precession of the vortex core, are found in these flows and may influence the combustion process in beneficial and adverse ways. In the present study, we investigate the occurrence and shape of self-excited hydrodynamic instabilities and their impact on heat release fluctuations and mixing characteristics over a wide range of operating conditions. We employ high-speed stereoscopic particle image velocimetry (S-PIV) and simultaneous OH*-chemiluminescence imaging to resolve the flow velocities and heat release distribution, respectively. The results reveal four different flame shapes: A detached annular flame, a long trumpet shaped flame, a V flame, and a very short flame anchored near the combustor inlet. The flame shapes were found to closely correlate with the reactivity of the mixture. Highly steam-diluted or very lean flames cause a detachment, whereas hydrogen fuel leads to very short flames. The detached flames feature a helical instability, which, in terms of frequency and shape, is similar to the isothermal case. A complete suppression of the helical structure is found for the V flame. Both the trumpet shaped flame and the very short flame feature helical instabilities of different frequencies and appearances. The phase-averaged OH*-chemiluminescence images show that the helical instabilities cause large-scale heat release fluctuations. The helical structure of the fluctuations is exploited to use a tomographic reconstruction technique. Furthermore, it is shown that the helical instability significantly enhances the mixing between the emanating jet and the central recirculation zone.

References

1.
Syred
,
N.
,
2006
, “
A Review of Oscillation Mechanisms and the Role of the Precessing Vortex Core (PVC) in Swirl Combustion Systems
,”
Prog. Energy Combust. Sci.
,
32
(
2
), pp.
93
161
.10.1016/j.pecs.2005.10.002
2.
Oberleithner
,
K.
,
Sieber
,
M.
,
Nayeri
,
C. N.
,
Paschereit
,
C. O.
,
Petz
,
C.
,
Hege
,
H.-C.
,
Noack
,
B. R.
, and
Wygnanski
,
I. J.
,
2011
, “
Three-Dimensional Coherent Structures in a Swirling Jet Undergoing Vortex Breakdown: Stability Analysis and Empirical Mode Construction
,”
J. Fluid Mech.
,
679
, pp.
383
414
.10.1017/jfm.2011.141
3.
Ruith
,
M. R.
,
Chen
,
P.
,
Meiburg
,
E.
, and
Maxworthy
,
T.
,
2003
, “
Three-Dimensional Vortex Breakdown in Swirling Jets and Wakes: Direct Numerical Simulation
,”
J. Fluid Mech.
,
486
, pp.
331
378
.10.1017/S0022112003004749
4.
Gallaire
,
F.
, and
Chomaz
,
J.-M.
,
2003
, “
Mode Selection in Swirling Jet Experiments: A Linear Stability Analysis
,”
J. Fluid Mech.
,
494
, pp.
223
253
.10.1017/S0022112003006104
5.
Roux
,
S.
,
Lartigue
,
G.
,
Poinsot
,
T.
,
Meier
,
U.
, and
Bérat
,
C.
,
2005
, “
Studies of Mean and Unsteady Flow in a Swirled Combustor Using Experiments, Acoustic Analysis, and Large Eddy Simulations
,”
Combust. Flame
,
141
(
1–2
), pp.
40
54
.10.1016/j.combustflame.2004.12.007
6.
Boxx
,
I.
,
Arndt
,
C.
,
Carter
,
C. D.
, and
Meier
,
W.
,
2010
, “
High-Speed Laser Diagnostics for the Study of Flame Dynamics in a Lean Premixed Gas Turbine Model Combustor
,”
Exp. Fluids
,
52
(
3
), pp.
555
567
.10.1007/s00348-010-1022-x
7.
Hermeth
,
S.
,
Staffelbach
,
G. M.
,
Gicquel
,
L. Y.
, and
Poinsot
,
T.
,
2014
, “
Bistable Flame Stabilization in Swirled Flames and Influence on Flame Transfer Functions
,”
Combust. Flame
,
161
(1)
, pp.
184
196
.10.1016/j.combustflame.2013.07.022
8.
Terhaar
,
S.
,
Oberleithner
,
K.
, and
Paschereit
,
C. O.
,
2014
, “
Impact of Steam-Dilution on the Flame Shape and Coherent Structures in Swirl-Stabilized Combustors
,”
Combust. Sci. Technol.
,
186
(7)
, pp.
889
911
.10.1080/00102202.2014.890597
9.
Oberleithner
,
K.
,
Terhaar
,
S.
,
Rukes
,
L.
, and
Paschereit
,
C. O.
,
2013
, “
Why Non-Uniform Density Suppresses the Precessing Vortex Core
,”
ASME J. Eng. Gas Turbines Power
,
135
(
12
), p.
121506
.10.1115/1.4025130
10.
Galley
,
D.
,
Ducruix
,
S.
,
Lacas
,
F.
, and
Veynante
,
D.
,
2011
, “
Mixing and Stabilization Study of a Partially Premixed Swirling Flame Using Laser Induced Fluorescence
,”
Combust. Flame
,
158
(
1
), pp.
155
171
.10.1016/j.combustflame.2010.08.004
11.
Göckeler
,
K.
,
Terhaar
,
S.
, and
Paschereit
,
C. O.
,
2013
, “
Residence Time Distribution in a Swirling Flow at Nonreacting, Reacting, and Steam-Diluted Conditions
,”
ASME J. Eng. Gas Turbines Power
,
136
(
4
), p. 041505.10.1115/1.4026000
12.
Schadow
,
K. C.
, and
Gutmark
,
E. J.
,
1992
, “
Combustion Instability Related to Vortex Shedding in Dump Combustors and Their Passive Control
,”
Prog. Energy Combust. Sci.
,
18
(
2
), pp.
117
132
.10.1016/0360-1285(92)90020-2
13.
Paschereit
,
C. O.
,
Gutmark
,
E. J.
, and
Weisenstein
,
W.
,
2000
, “
Excitation of Thermoacoustic Instabilities by Interaction of Acoustics and Unstable Swirling Flow
,”
AIAA J.
,
38
(
6
), pp.
1025
1034
.10.2514/2.1063
14.
Stöhr
,
M.
,
Boxx
,
I.
,
Carter
,
C. D.
, and
Meier
,
W.
,
2012
, “
Experimental Study of Vortex-Flame Interaction in a Gas Turbine Model Combustor
,”
Combust. Flame
,
159
(
8
), pp.
2636
2649
.10.1016/j.combustflame.2012.03.020
15.
Moeck
,
J. P.
,
Bourgouin
,
J.-F.
,
Durox
,
D.
,
Schuller
,
T.
, and
Candel
,
S.
,
2012
, “
Nonlinear Interaction Between a Precessing Vortex Core and Acoustic Oscillations in a Turbulent Swirling Flame
,”
Combust. Flame
,
159
(
8
), pp.
2650
2668
.10.1016/j.combustflame.2012.04.002
16.
Samarasinghe
,
J.
,
Peluso
,
S.
,
Szedlmayer
,
M.
,
De Rosa
,
A.
,
Quay
,
B. D.
, and
Santavicca
,
D. A.
,
2013
, “
Three-Dimensional Chemiluminescence Imaging of Unforced and Forced Swirl-Stabilized Flames in a Lean Premixed Multi-Nozzle Can Combustor
,”
ASME J. Eng. Gas Turbines Power
,
135
(
10
), p. 101503.10.1115/1.4024987
17.
Acharya
,
V. S.
,
Shin
,
D.-H.
, and
Lieuwen
,
T.
,
2013
, “
Premixed Flames Excited by Helical Disturbances: Flame Wrinkling and Heat Release Oscillations
,”
J. Propul. Power
,
29
(
6
), pp.
1282
1291
.10.2514/1.B34883
18.
Lieuwen
,
T.
, and
Yang
,
V.
,
2005
,
Combustion Instabilities in Gas Turbine Engines: Operational Experience, Fundamental Mechanisms, and Modeling
(
Progress in Astronautics and Aeronautics
, Vol. 210), American Institute of Aeronautics and Astronautics, Reston, VA.10.2514/4.866807
19.
Durox
,
D.
,
Schuller
,
T.
,
Noiray
,
N.
, and
Candel
,
S.
,
2009
, “
Experimental Analysis of Nonlinear Flame Transfer Functions for Different Flame Geometries
,”
Proc. Combust. Inst.
,
32
(
1
), pp.
1391
1398
.10.1016/j.proci.2008.06.204
20.
Thumuluru
,
S.
, and
Lieuwen
,
T.
,
2009
, “
Characterization of Acoustically Forced Swirl Flame Dynamics
,”
Proc. Combust. Inst.
,
32
(
2
), pp.
2893
2900
.10.1016/j.proci.2008.05.037
21.
Schimek
,
S.
,
Göke
,
S.
,
Schrödinger
,
C.
, and
Paschereit
,
C. O.
,
2012
, “
Flame Transer Measurements With CH4 and H2 Fuel Mixtures at Ultra Wet Conditions in a Swirl Stabilized Premixed Combustor
,”
ASME
Paper No. GT2012-69788.10.1115/GT2012-69788
22.
Leuckel
,
W.
,
1967
, “
Swirl Intensities, Swirl Types and Energy Losses of Different Swirl Generating Devices
,” International Flame Foundation, Ijmuiden, The Netherlands, IFRF Doc. Nr. G02/a/16.
23.
Terhaar
,
S.
,
Bobusch
,
B. C.
, and
Paschereit
,
C. O.
,
2012
, “
Effects of Outlet Boundary Conditions on the Reacting Flow Field in a Swirl-Stabilized Burner at Dry and Humid Conditions
,”
ASME J. Eng. Gas Turbines Power
,
134
(
11
), p.
111501
.10.1115/1.4007165
24.
Lawson
,
N. J.
, and
Wu
,
J.
,
1997
, “
Three-Dimensional Particle Image Velocimetry: Experimental Error Analysis of a Digital Angular Stereoscopic System
,”
Meas. Sci. Technol.
,
8
(12), pp.
1455
1464
.10.1088/0957-0233/8/12/009
25.
Berkooz
,
G.
,
Holmes
,
P.
, and
Lumley
,
J. L.
,
1993
, “
The Proper Orthogonal Decomposition in the Analysis of Turbulent Flows
,”
Annu. Rev. Fluid Mech.
,
25
(
1
), pp.
539
575
.10.1146/annurev.fl.25.010193.002543
26.
Moeck
,
J. P.
,
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
(
4
), p.
1498
.10.1007/s00348-013-1498-2
27.
Goodwin
,
D. G.
,
2003
, “
An Open Source, Extensible Software Suite for CVD Process Simulation
.” CVD XVI/EuroCVD-14, Paris, France, Apr. 27–May 2, pp. 155–162.
28.
Smith
,
G. P.
,
Golden
,
D. M.
,
Frenklach
,
M.
,
Moriarty
,
N. W.
,
Eiteneer
,
B.
,
Goldenberg
,
M.
,
Bowman
,
C. T.
,
Hanson
,
R. K.
,
Song
,
S.
,
Gardiner
,
W. C.
,
Lissianski
,
V. V.
, and
Qin
,
Z.
,
2000
, “GRI-Mech 3.0,” Gas Research Institute, Chicago, IL, available at: http://www.me.berkeley.edu/gri_mech/
29.
Burke
,
M. P.
,
Chaos
,
M.
,
Ju
,
Y.
,
Dryer
,
F. L.
, and
Klippenstein
,
S. J.
,
2012
, “
Comprehensive H2/O2 Kinetic Model for High-Pressure Combustion
,”
Int. J. Chem. Kinet.
,
44
(
7
), pp.
444
474
.10.1002/kin.20603
30.
Krüger
,
O.
,
Duwig
,
C.
,
Terhaar
,
S.
, and
Paschereit
,
C. O.
,
2013
, “
Large Eddy Simulations of Hydrogen Oxidation at Ultra-Wet Conditions in a Model Gas Turbine Combustor Applying Detailed Chemistry
,”
ASME J. Eng. Gas Turbines Power
,
135
(
2
), p. 021501.10.1115/1.4007718
31.
Terhaar
,
S.
,
Göckeler
,
K.
,
Schimek
,
S.
,
Göke
,
S.
, and
Paschereit
,
C. O.
,
2011
, “
Non-Reacting and Reacting Flow in a Swirl-Stabilized Burner for Ultra-Wet Combustion
,”
AIAA
Paper No. 2011-3584.10.2514/6.2011-3584
32.
Stöhr
,
M.
,
Sadanandan
,
R.
, and
Meier
,
W.
,
2011
, “
Phase-Resolved Characterization of Vortex-Flame Interaction in a Turbulent Swirl Flame
,”
Exp. Fluids
,
51
(
4
), pp.
1153
1167
.10.1007/s00348-011-1134-y
33.
Terhaar
,
S.
,
Oberleithner
,
K.
, and
Paschereit
,
C. O.
,
2014
, “
Key Parameters Governing the Precessing Vortex Core in Reacting Flows: An Experimental and Analytical Study
,”
Proc. Combust. Inst.
(in press).10.1016/j.proci.2014.07.035
34.
Coats
,
C.
,
1996
, “
Coherent Structures in Combustion
,”
Prog. Energy Combust. Sci.
,
22
(5)
, pp.
427
509
.10.1016/S0360-1285(96)00011-1
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