Abstract
Swirling combustion is widely applied in various applications such as gas turbines, utility boilersor waste incinerators. This article contributes to the ongoing research by providing experimentaldata that are gathered in the mixing zone of a lifted swirling premixed natural gas flame. Theobjective of this paper is fivefold: (1) to introduce the lifted swirling flame featuring lowNO x emissions (2) to provide experimental data such as major species distributions, temperature and streamlines of the flow pattern, (3) to report on velocity bias in probability density function (PDF) distributions and to present PDF sequences of velocities in medium scale swirling flows, (4) to make an assessment on the local small-scale turbulence that is present in the swirling mixinglayer and (5) to provide new experimental data for model verification and development.
The PDFs are corrected in order to compensate for the velocity bias phenomenon, which is typicalfor randomly sampled LDA data. Sequences of axial PDF data are presented and measurement locationsof interest are selected to look at the PDF characteristics of the internal and externalrecirculation zones, the mixing layer and the onset of the reacting flow into detail. The mixinglayer PDFs covered a wide velocity range and revealed bimodality; even the concept ofmulti-modality is suggested and explored. Analysis showed that a sum of two Gaussian distributionscan accurately envelop the experimental PDFs. The reason for this broadband turbulence behavior isto be found in combination of precessing and flapping motion of the flow structures, and also incombustion generated instabilities of the lifted flame. As a result, the flame brush is wide (largescale motion) and the mixing (small-scale turbulence) flattens any high temperatures in thecombustion process.
The multi-scale turbulence concept is subsequently used to make anassessment of the local turbulence characteristics in the mixing layer.The idea is that the PDFs capture both contributions of the flow-inherent fine grain turbulence (u′ l ) which is superposed on slowlarge scale fluctuating structures. It is this u′ l that will be of interest in continued research on the classification of the lifted flame into acombustion regime diagram (e.g. Borghi diagram). Finally, the bimodalitycharacter in reacting flows and the prediction of large-scale structuresmay be a challenge for LES researchers.
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References
Beér, J.M. and Chigier, N.A., Combustion Aerodynamics. Robert E. Krieger (1983).
Chakravarthy, V.K. and Menon, S., Large eddy simulation of turbulent premixed flames in the flamelet regime. Combust. Sci. Technol. 162 (2001) 175–222.
Duarte, D., Ferrao, P. and Heitor, M.V., Turbulence statistics and scalar transport in highly sheared premixed flames. Flow, Turbulence and Combustion 60(4) (1999) 361–376.
Edwards, R.V., Report of the special panel on statistical particle bias problems in laser anemometry. J. Fluids Engrg. 109 (1987) 89–93.
Escudier, M.P. and Keller, J.J., Recirculation in swirling flow: A manifestation of vortex breakdown. AIAA J. 34(3) (1985) 572–579.
Fujii, S., Eguchi, K. and Gomi, M., Swirling jets with and without combustion. AIAA J. 19(11) (1981) 1438–1442.
George, W.K., Processing of random signals. In: Proceedings of the Dynamic Flow Conference, Baltimore, MD, September 18-21 (1987) pp. 757–793.
Goldin, F.C., Depsky, J.S. and Lee, S.L., Velocity field characteristics of a swirling flow combustor. AIAA J. 23(1) (1985) 95–102.
Gupta, A.K., Beér, J.M. and Swithenbank, J., Concentric multi-annular swirl burner: Stability limits and emission characteristics. Proc. Combust. Inst. 16 (1977) 79–91.
Lawn, C.J., Principles of Combustion Engineering for Boilers. Academic Press, London (1987).
Lilley, D.G., Swirl flows in combustion: A review. AIAA J. 15(8) (1977) 1063–1078.
Mi, J., Nathan, G.J. and Luxton, R.E., Mixing characteristics of a flapping jet from a self-exciting nozzle. Flow, Turbulence and Combustion 67(1) (2001) 1–23.
Nathan, G.J., Luxton, R.E. and Smart, J.P., Reduced NO emissions and enhanced large scale turbulence from a precessing jet burner. Proc. Combust. Inst. 23 (1992) 1399–1405.
Petrie, H.L., Samimy, M. and Addy, A.L., Laser doppler velocity bias in separated turbulent flows. Exp. Fluids 6 (1988) 80–88.
Qi, S., Gupta, A.K. and Lewis, M.J., Effect of swirl on combustion characteristics in premixed flames. In: Proceedings of the ASME Internationall Gas Turbine and Aeroengine Congres, Orlando, FL, June 2-5. ASME, New York (1997).
Schmittel, P., Gunther, B., Lenze, B., Leuckel, W. and Bockhorn, H., Turbulent swirling flames. Proc. Combust. Inst. 28 (2000) 303–308.
Syred, N. and Beér, J.M., Combustion in swirling flows: A review. Combustion and Flame 23 (1974) 143–201.
Syred, N., Fick, W., O'doherty, T. and Griffiths, A.J., The effect of the precessing vortex core on combustion in a swirl burner. Combust. Sci. and Tech. 125 (1997) 139–157.
Tangirala, V., Chen, R. and Driscoll, J.F., Effects of heat release and swirl on the recirculation within swirl-stabilized flames. Combust. Sci. Technol. 51 (1987) 75–95.
Vanoverberghe, K., Van den Bulck, E., Hübner, W. and Tummers, M., Multiflame patterns in swirl-driven partially premixed natural gas combustion. ASME, J. Engrg. Gas Turbines Power 125 (2003) 40–45.
Vanoverberghe, K., Van den Bulck, E. and Tummers, M., Confined annular swirling jet combustion. Combust. Sci. Technol., 175(3) (2003) 545–578.
Weber, R. and Dugué, J., Combustion accelerated swirling flows in high confinements. Progr. Energy Combustion Sci. 18 (1992) 349–367.
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Vanoverberghe, K., Van den Bulck, E. & Tummers, M. Flow Structure of Lifted Swirling Jet Flames. Flow, Turbulence and Combustion 73, 25–47 (2004). https://doi.org/10.1023/B:APPL.0000044298.57545.4a
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DOI: https://doi.org/10.1023/B:APPL.0000044298.57545.4a