Abstract
This paper describes an experimental study investigating the non-linear response of lean premixed air/ethylene flames to strong inlet velocity perturbations of two frequencies. The combustor has a centrally-placed bluff body and a short quartz section. The annulus between the bluff body and the flow tube, which also housed the acoustic pressure transducers, allowed the reactants into the combustor. The inlet flow was perturbed using loudspeakers. High speed laser tomography, OH* chemiluminescence and OH Planar Laser Induced Fluorescence (PLIF) have been used for flow visualization, heat release and flame surface density (FSD) measurements respectively. The heat release fluctuations increased initially linearly with inlet velocity amplitude for a single frequency forcing, with saturation occurring after forcing amplitudes of around 15% of the bulk velocity, which was found to occur due to vortex roll up and subsequent flame annihilation. The introduction of energy at the second frequency (i.e, the harmonic) was found to change the vortex formation and shedding frequency, depending on the level of forcing. This resulted in a non-linear flame response transfer function (defined as the amplitude of unsteady heat release divided by the amplitude of velocity perturbation at the fundamental) whose amplitude depended greatly on the amount of harmonic content present in the perturbations. The introduction of higher harmonics reduced the flame annihilation events, which are responsible for saturation, thus reducing non-linearity in the amplitude dependence of the flame response. These results were further verified using sequential time-resolved OH PLIF measurements. The findings from this study suggest that the acoustic response of the flame was mostly due to flame area variation effected by modulation of the annular jet and evolution of the shear layers.
Similar content being viewed by others
References
Armitage, C.A., Balachandran, R., Mastorakos, E., Cant, R.S.: Numerical investigation of the non-linear response of turbulent premixed flames to imposed inlet velocity oscillations. Combust. Flame 146(3), 419–436 (2006)
Ayoola, B.O., Balachandran, R., Frank, J.H., Mastorakos, E., Kaminski, C.F.: Spatially-resolved heat release measurements in turbulent premixed flames. Combust. Flame 144(1), 1–16 (2006)
Balachandran, R., Ayoola, B.O., Kaminski, C.F., Dowling, A.P., Mastorakos, E.: Experimental investigation of the non-linear response of turbulent premixed flames to imposed inlet velocity oscillations. Combust. Flame 143(1), 37–55 (2005a)
Balachandran, R., Dowling, A.P., Mastorakos, E.: Response of turbulent premixed flames subjected to inlet velocity and equivalence ratio perturbations. In: Proceedings of European Combustion Meeting, Louvain la Neuve, Belgium, 3–6 April 2005b
Bellows, B.D., Lieuwen, T.: Nonlinear response of a premixed combustor to forced acoustic oscillations. In: 42nd Aerospace Science Meeting and Exhibit, Reno, NV, USA (AIAA-2004-0455), 7–10 January 2004
Brookes, S.J., Cant, R.S., Dupere, I.D.J., Dowling, A.P.: Computational modeling of self-excited combustion instabilities. J. Eng. Gas Turbine Power 123, 322–326 (2001)
Cala, C.E.C., Fernandes, E.C., Heitor, M.V.: Analysis of oscillating shear layer. In: Symposium on Application of Laser Techniques and Fluid Mehanics LISBOA, Portugal, pp. 11, 2002
Candel, S.: Combustion dynamics and control: progress and challenges. In: Proceedings of the Combustion Institute, vol. 29, pp. 1–28. Combustion Institute, Pittsburgh (2002)
Cerecedo, L.M., Aisa, L., Garcia, J.A., Santolaya, J.L.: Changes in a coflowing jet structure caused by acoustic forcing. Exp. Fluids 36, 867–878 (2004)
Chen, T., Chen, C.: Experimental study of flame driving function in an acoustically excited duct with anchored flames. Exp. Fluids 31, 457–464 (2001)
Cho, S.K., Yoo, J.Y., Choi, H.: Vortex pairing in an axisymmetric jet using two-frequency acoustic forcing at low to moderate Strouhal numbers. Exp. Fluids 25, 305–315 (1998)
Dawson, J.R., Rodriguez-Martinez, V.M., Syred, N., O’Doherty, T.: The effect of combustion instability on the structure of recirculation zones in confined swirling flames. Combust. Sci. Technol. 177(12), 2349–2371 (2005)
Dowling, A.P.: The 1999 Lanchester lecture- vortices, sound and flame -damaging combination. Aeronaut. J. 104(1033), 105–116 (2000)
Dowling, A.P., Morgans, A.S.: Feedback control of combustion oscillations. Ann. Rev. Fluid Mech. 37, 151–182 (2005)
Dowling, A.P., Stow, S.R.: Acoustic analysis of gas turbine combustors. J. Propuls. Power 19(5), 751–764 (2003)
Ducruix, S., Durox, D., Candel, S.: Theoretical and experimental determinations of the transfer function of a laminar premixed flame. In: Proceedings of the Combustion Institute, vol. 28, pp. 765–773. Combustion Institute, Pittsburgh (2000)
Durox, D., Ducruix, S., Baillot, F.: Strong acoustic forcing on conical premixed flames. In: Proceedings of the Combustion Institute, vol. 27, 883–889. Combustion Institute, Pittsburgh (1998)
Giezendanner-Thoben, R., Meier, U., Meier, M., Aigner, M.: Phase-locked temperature measurements by two-line OH PLIF thermometry of a self-excited combustion instability in a gas turbine model combustor. Flow, Turbul. Combust. 75, 317–353 (2005)
Gutmark, E., Parr, T.P., Parr, D.M., Schadow, K.C.: Planar imaging of vortex dynamics in flames. Transcations of ASME. J. Heat Transf. 111, 148–155 (1989)
Harper, J., Johnson, C., Neumeir, Y., Lieuwen, T., Zinn, B.T.: Experimental investigation of the nonlinear flame response to flow disturbances in a gas turbine combustor. 39th AIAA Aerospace Sciences Meeting and Exhibit, Reno NV (01 0486), 8–11 January 2001
Joos, F., Vortmeyer, D.: Self-excited oscillations in combustion chambers with premixed flames and several frequencies. Combust. Flame 65, 253–262 (1986)
Külsheimer, C., Büchner, H.: Combustion dynamics of turbulent swirling flames. Combust. Flame 131, 70–84 (2002)
Lee, J.G., Santavicca, D.A.: Experimental diagnostics for the study of combustion instabilities in lean premixed combustors. J. Propuls. Power 19(5), 735–750 (2003)
Lee, S.Y., Seo, S., Broad, J.C., Pal, S., Santoro, R.J.: An experimental estimation of mean reaction rate and flame structure during combustion instability in a lean premixed gas turbine combustor. In: Proceedings of the Combustion Institute, vol. 28, pp. 775–782. Combustion Institute, Pittsburgh (2000)
Lieuwen, T.: Modeling premixed combustion-acoustic wave interaction: a review. J. Propuls. Power 19(5), 765–781 (2003)
McManus, K.R., Poinsot, T., Candel, S.: A review of active control of combustion instabilities. Prog. Engery Combust. Sci. 19(1), 1–29 (1993)
Meier, W., Weigand, P., Duan, X.R., Giezendanner-Thoben, R.: Detailed characterization of the dynamics of thermoacoustic pulsations in a lean premixed swirl flame. Combust. Flame 150, 2–26 (2007)
Merk, H.J.: An analysis of unstable combustion of premixed gases. In: Proceedings of the Combustion Institute, vol. 6, pp. 500–511. Combustion Institute, Pittsburgh (1956)
Merzkirch, W.: Flow Visualization, 2nd edn. Academic Press, Orlando (1987)
Paschereit, C.O., Gutmark, E., Weisenstein, W.: Excitation of thermoacoustic instabilities by interaction of acoustics and unstable swirling flows. AIAA J. 38(6), 1025–1034 (2000)
Peracchio, A.A., Proscia, W.M.: Nonlinear heat-release/ acoustic model for thermoacoustic instability in lean premixed combustors. J. Eng. Gas Turbine Power 121, 415–421 (1999)
Poinsot, T.J., Trouve, A.C., Veynante, D.P., Candel, S., Esposito, E.: Vortex-driven acoustically coupled combusiton instabilities. J. Fluid Mech. 177, 265–292 (1987)
Pun, W., Palm, S.L., Culick, F.E.C.: Combustion dynamics of an acoustically forced flame. Combust. Sci. Technol. 175(3), 499–521 (2003)
Schlüter, J.U.: Large-Eddy Simulations of Combustion Instability Suppression by Static Turbulence Control. Annual Research Briefs, Center for Turbulence Research, Standford University, USA (2001)
Schuller, T., Durox, D., Candel, S.: A unified model for the prediction of laminar flame transfer functions: comparisons between conical and V-flame dynamics. Combust. Flame 134, 21–34 (2003)
Seybert, A.F., Ross, D.F.: Experimental determination of acoustic properties using a two-microphone random excitation technique. J. Acoust. Soc. Am. 61, 1362–1370 (1977)
Truffin, K., Poinsot, T.: Comparison and extension of methods for acoustic identification of burners. Combust. Flame 142(4), 388–400 (2005)
Wakelin, S.L., Riley, N.: On the formation and propagation of vortex rings and pairs of vortex rings. J. Fluid Mech. 332(121–139) (1997)
Wasle, J., Winkler, A., Sattelmayer, T.: Spatial coherence of the heat release fluctuations in turbulent jet and swirl flames. Flow Turbul. Combust. 75, 29–50 (2005)
Weigand, P., Meier, W., Duan, X.R., Giezendanner-Thoben, R., Meier, U.: Laser diagnostic study of the mechanism of a periodic combustion instability in a gas turbine model combustor. Flow Turbul. Combust. 75, 275–292 (2005)
Zhou, M., Wyganski, I.: The response of a mixing layer formed between parallel streams to a concomitant excitation at two frequencies. J. Fluid Mech. 441, 139–168 (2001)
Zhu, M., Dowling, A.P., Bray, K.N.C.: Self-excited oscillations in combustors with spray atmoizers. J. Eng. Gas Turbine Power 123, 779–786 (2001)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Balachandran, R., Dowling, A.P. & Mastorakos, E. Non-linear Response of Turbulent Premixed Flames to Imposed Inlet Velocity Oscillations of Two Frequencies. Flow Turbulence Combust 80, 455–487 (2008). https://doi.org/10.1007/s10494-008-9139-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10494-008-9139-1