0
Research Papers: Gas Turbines: Combustion, Fuels, and Emissions

Boundary Layer Flashback in Premixed Hydrogen–Air Flames With Acoustic Excitation

[+] Author and Article Information
Vera Hoferichter

Lehrstuhl für Thermodynamik,
Technische Universität München,
Garching 85748, Germany
e-mail: hoferichter@td.mw.tum.de

Thomas Sattelmayer

Lehrstuhl für Thermodynamik,
Technische Universität München,
Garching 85748, Germany

1Corresponding author.

Contributed by the Combustion and Fuels Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received August 6, 2017; final manuscript received August 9, 2017; published online November 21, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 140(5), 051502 (Nov 21, 2017) (9 pages) Paper No: GTP-17-1438; doi: 10.1115/1.4038128 History: Received August 06, 2017; Revised August 09, 2017

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.

FIGURES IN THIS ARTICLE
<>
Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

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
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. [CrossRef]
Lieuwen, T. , and Yang, V. , 2005, Combustion Instabilities in Gas Turbine Engines, American Institute of Aeronautics and Astronautics, Reston, VA.
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. [CrossRef]
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. [CrossRef]
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. [CrossRef]
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.
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. [CrossRef]
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. [CrossRef]
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.
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
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. [CrossRef]
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.
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. [CrossRef]
Davu, D. , Franco, R. , and Choudhuri, A. , 2005, “ Investigation on Flashback Propensity of Syngas Premixed Flames,” AIAA Paper No. 2005-3585.
Subramanya, M. , and Choudhuri, A. , 2007, “ Investigation of Combustion Instability Effects on the Flame Characteristics of Fuel Blends,” AIAA Paper No. 2007-4796.
Dam, B. , Love, N. , and Choudhuri, A. , 2011, “ Flashback Propensity of Syngas Fuels,” Fuel, 90(2), pp. 618–625. [CrossRef]
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
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. [CrossRef]
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.
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
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. [CrossRef]
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. [CrossRef]
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. [CrossRef]
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

Figures

Grahic Jump Location
Fig. 1

Flashback test rig with acoustic excitation

Grahic Jump Location
Fig. 2

Measurement setup: (a) CTA, (b) OH* Chemiluminescence

Grahic Jump Location
Fig. 3

Normalized velocity oscillation amplitude at the burner exit averaged over 190 excitation periods for varying excitation frequencies. 2T2 and 6T2 represent configurations with two and six speakers of type 2

Grahic Jump Location
Fig. 4

Flashback limits of the reference configuration RC compared to test rig data without speaker section

Grahic Jump Location
Fig. 5

Flashback limits of configuration 2T1-135 for varying excitation amplitudes in comparison to reference case RC

Grahic Jump Location
Fig. 6

Flashback limits of configurations 2T1-120 and 2T2-115 for varying excitation amplitudes in comparison to reference case RC

Grahic Jump Location
Fig. 7

Flashback limits of configurations 2T2-330 and 6T2-350 for varying excitation amplitudes in comparison to reference case RC

Grahic Jump Location
Fig. 8

Flashback limits of configurations 6T1-135, 6T1-120, and 6T2-135 in comparison to reference case RC

Grahic Jump Location
Fig. 9

Influence of excitation amplitude and frequency on flashback limits at constant air mass flow rates. Lines mark linear fits for low frequencies (dashed) and intermediate frequencies (solid). (a) Low velocity: m˙air=20 g/s and (b) high velocity: m˙air=24 g/s.

Grahic Jump Location
Fig. 10

OH* images of high excitation amplitude flashback at f=120 Hz, A=23 %, U¯FB=14.5 m/s, and ϕFB=0.48 (top view). Flow direction is from left to right.

Grahic Jump Location
Fig. 11

Flame tip trajectory during flashback for different excitation amplitudes. (a) Low frequencies (120 Hz) and (b) intermediate frequencies (330–350 Hz).

Grahic Jump Location
Fig. 12

Flashback limits in terms of minimum flow velocities for low frequency excitation compared to unconfined (RC) and confined [19] flames

Grahic Jump Location
Fig. 13

Flashback limits in terms of maximum flow velocities for low frequency excitation compared to unconfined (RC) and confined [19] flames

Grahic Jump Location
Fig. 14

Flashback limits in terms of minimum and maximum flow velocities for low and high excitation amplitudes comparedto unconfined (RC) and confined [19] flames. (a) Low frequencies (115–135 Hz) and (b) intermediate frequencies (330–350 Hz).

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In