Lean premixed combustion is prevailing in gas turbines to minimize nitrogen oxide emissions. However, this technology bears the risk of flame flashback and thermoacoustic instabilities. Thermoacoustic instabilities induce velocity oscillations at the burner exit which, in turn, can trigger flame flashback. This article presents an experimental study at ambient conditions on the effect of longitudinal acoustic excitation on flashback in the boundary layer of a channel burner. The acoustic excitation simulates the effect of thermoacoustic instabilities. Flashback limits are determined for different excitation frequencies characterizing intermediate frequency dynamics in typical gas turbine combustors (100–350 Hz). The excitation amplitude is varied from 0% to 36% of the burner bulk flow velocity. For increasing excitation amplitude, the risk of flame flashback increases. This effect is strongest at low frequencies. For increasing excitation frequency, the influence of the velocity oscillations decreases as the flame has less time to follow the changes in bulk flow velocity. Two different flashback regimes can be distinguished based on excitation amplitude. For low excitation amplitudes, flashback conditions are reached if the minimum flow velocity in the excitation cycle falls below the flashback limit of unexcited unconfined flames. For higher excitation amplitudes, where the flame starts to periodically enter the burner duct, flashback is initiated if the maximum flow velocity in the excitation cycle is lower than the flashback limit of confined flames. Consequently, flashback limits of confined flames should also be considered in the design of gas turbine burners as a worst case scenario.

References

References
1.
Eichler
,
C.
,
2011
, “
Flame Flashback in Wall Boundary Layers of Premixed Combustion Systems
,”
Ph.D. thesis
, Technische Universität München, München, Germany.https://www.td.mw.tum.de/fileadmin/w00bso/www/Forschung/Dissertationen/Eichler.pdf
2.
Keller
,
J.
,
Vaneveld
,
L.
,
Korschelt
,
D.
,
Hubbard
,
G.
,
Ghoniem
,
A.
,
Daily
,
J.
, and
Oppenheim
,
A.
,
1982
, “
Mechanism of Instabilities in Turbulent Combustion Leading to Flashback
,”
AIAA J.
,
20
, pp.
254
262
.
3.
Lieuwen
,
T.
, and
Yang
,
V.
,
2005
,
Combustion Instabilities in Gas Turbine Engines
, American Institute of Aeronautics and Astronautics, Reston, VA.
4.
Kiesewetter
,
F.
,
Konle
,
M.
, and
Sattelmayer
,
T.
,
2007
, “
Analysis of Combustion Induced Vortex Breakdown Driven Flame Flashback in a Premix Burner With Cylindrical Mixing Zone
,”
ASME J. Eng. Gas Turbines Power
,
129
(
4
), pp.
929
936
.
5.
Fritz
,
J.
,
Kröner
,
M.
, and
Sattelmayer
,
T.
,
2004
, “
Flashback in a Swirl Burner With Cylindrical Premixing Zone
,”
ASME J. Eng. Gas Turbines Power
,
126
(
2
), pp.
276
283
.
6.
Burmberger
,
S.
, and
Sattelmayer
,
T.
,
2011
, “
Optimization of the Aerodynamic Flame Stabilization for Fuel Flexible Gas Turbine Premix Burners
,”
ASME J. Eng. Gas Turbines Power
,
133
(
10
), p.
101501
.
7.
Baumgartner
,
G.
, and
Sattelmayer
,
T.
,
2013
, “
Experimental Investigation of the Flashback Limits and Flame Propagation Mechanisms for Premixed Hydrogen-Air Flames in Non-Swirling and Swirling Flow
,”
ASME
Paper No. GT2013-94258.
8.
Eichler
,
C.
, and
Sattelmayer
,
T.
,
2010
, “
Experiments on Flame Flashback in a Quasi-2D Turbulent Wall Boundary Layer for Premixed Methane-Hydrogen–Air Mixtures
,”
ASME J. Eng. Gas Turbines Power
,
133
(1), p.
011503
.
9.
Eichler
,
C.
, and
Sattelmayer
,
T.
,
2012
, “
Premixed Flame Flashback in Wall Boundary Layer Studied by Long-Distance Micro-PIV
,”
Exp. Fluids
,
52
(
2
), pp.
347
360
.
10.
Baumgartner
,
G.
, and
Sattelmayer
,
T.
,
2013
, “
Experimental Investigation on the Effect of Boundary Layer Fluid Injection on the Flashback Propensity of Premixed Hydrogen–Air Flames
,”
ASME
Paper No. GT2013-94266.
11.
Baumgartner
,
G.
,
Boeck
,
L. R.
, and
Sattelmayer
,
T.
,
2014
, “
Investigation of the Flame-Flow Interaction during Flame Flashback in a Generic Premixed Combustion System by Means of High-Speed μ-PIV and μ-PLIF
,”
16th International Symposium on Flow Visualization
, Okinawa, Japan, June 24–28, Paper No.
ISFV16-1135
.https://www.researchgate.net/publication/271838906_Investigation_of_the_Flame-Flow_Interaction_during_Flame_Flashback_in_a_Generic_Premixed_Combuston_System_by_Means_of_High-Speed_Micro-PIV_and_Micro-PLIF
12.
Hoferichter
,
V.
,
Hirsch
,
C.
, and
Sattelmayer
,
T.
,
2017
, “
Prediction of Confined Flame Flashback Limits Using Boundary Layer Separation Theory
,”
ASME J. Eng. Gas Turbines Power
,
139
(2), p.
021505
.
13.
Hoferichter
,
V.
,
Hirsch
,
C.
, and
Sattelmayer
,
T.
,
2016
, “
Analytic Prediction of Unconfined Boundary Layer Flashback Limits in Premixed Hydrogen–Air Flames
,”
Combust. Theory Modell.
,
21
(
3
), pp. 328–418.
14.
Thibaut
,
D.
, and
Candel
,
S.
,
1998
, “
Numerical Study of Unsteady Turbulent Premixed Combustion: Application to Flashback Simulation
,”
Combust. Flame
,
113
(1–2), pp.
53
65
.
15.
Davu
,
D.
,
Franco
,
R.
, and
Choudhuri
,
A.
,
2005
, “
Investigation on Flashback Propensity of Syngas Premixed Flames
,”
AIAA
Paper No. 2005-3585.
16.
Subramanya
,
M.
, and
Choudhuri
,
A.
,
2007
, “
Investigation of Combustion Instability Effects on the Flame Characteristics of Fuel Blends
,”
AIAA
Paper No. 2007-4796.
17.
Dam
,
B.
,
Love
,
N.
, and
Choudhuri
,
A.
,
2011
, “
Flashback Propensity of Syngas Fuels
,”
Fuel
,
90
(
2
), pp.
618
625
.
18.
Sabel'nikov
,
V.
,
Brossard
,
C.
,
Orain
,
M.
,
Grisch
,
F.
,
Barat
,
M.
,
Ristori
,
A.
, and
Gicquel
,
P.
,
2008
, “
Thermo-Acoustic Instabilities in a Backward-Facing Step Stabilized Lean-Premixed Flame in High Turbulence Flow
,”
14th International Symposium on Applications of Laser Techniques to Fluid Mechanics
, Lisbon, Portugal, July 7–10.http://ltces.dem.ist.utl.pt/lxlaser/lxlaser2008/papers/09.2_4.pdf
19.
Eichler
,
C.
,
Baumgartner
,
G.
, and
Sattelmayer
,
T.
,
2012
, “
Experimental Investigation of Turbulent Boundary Layer Flashback Limits for Premixed Hydrogen-Air Flames Confined in Ducts
,”
ASME J. Eng. Gas Turbines Power
,
134
(
1
), p.
011502
.
20.
Hoferichter
,
V.
,
Keleshtery
,
P. M.
,
Hirsch
,
C.
,
Sattelmayer
,
T.
, and
Matsumura
,
Y.
,
2016
, “
Influence of Boundary Layer Air Injection on Flashback of Premixed Hydrogen–Air Flames
,”
ASME
Paper No. GT2016-56156.
21.
Khitrin
,
L.
,
Moin
,
P.
,
Smirnov
,
D.
, and
Shevchuk
,
V.
,
1965
, “
Peculiarities of Laminar- and Turbulent-Flame Flashbacks
,”
Symp. (Int.) Combust.
,
10
(1), pp.
1285
1291
.https://doi.org/10.1016/S0082-0784(65)80263-6
22.
Baumgartner
,
G.
,
Boeck
,
L. R.
, and
Sattelmayer
,
T.
,
2015
, “
Experimental Investigation of the Transition Mechanism from Stable Flame to Flashback in a Generic Premixed Combustion System With High-Speed Micro-PIV and Micro-PLIF Combined With Chemiluminescence Imaging
,”
ASME J. Eng. Gas Turbines Power
,
138
(
2
), p.
021501
.
23.
Gruber
,
A.
,
Sankaran
,
R.
,
Hawkes
,
E. R.
, and
Chen
,
J. H.
,
2010
, “
Turbulent Flame-Wall Interaction: A Direct Numerical Simulation Study
,”
J. Fluid Mech.
,
658
, pp.
5
32
.
24.
Gruber
,
A.
,
Chen
,
J. H.
,
Valiev
,
D.
, and
Law
,
C. K.
,
2012
, “
Direct Numerical Simulation of Premixed Flame Boundary Layer Flashback in Turbulent Channel Flow
,”
J. Fluid Mech.
,
709
, pp.
516
542
.
25.
Baumgartner
,
G.
,
2014
, “
Flame Flashback in Premixed Hydrogen–Air Combustion Systems
,”
Ph.D. thesis
, Technische Universität München, Münich, Germany.https://www.td.mw.tum.de/fileadmin/w00bso/www/Forschung/Dissertationen/baumgaertner15.pdf
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