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Influence of transversal acoustic excitation of the burner approach flow on the flame structure / Martin Hauser in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 4 (Avril 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 4 (Avril 2011) . - 08 p. Titre : Influence of transversal acoustic excitation of the burner approach flow on the flame structure Type de document : texte imprimé Auteurs : Martin Hauser, Auteur ; Manuel Lorenz, Auteur ; Thomas Sattelmayer, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Acoustics  Electric  power  generation  Engines  Flames  Gas  turbines  Oscillations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Modern large gas turbines for power generation have multiple burners, which are distributed around the circumference of the engine and which generate flames in combustors of either annular or can-annular geometry. In both cases, considering only the axial modes has proven to be insufficient for the assessment of the thermoacoustic stability. An adequate analysis requires consideration of the circumferential acoustic coupling generated by the acoustic field in the upstream and downstream annuli and the open passages between the cans, respectively. As in annular combustors, the particularly critical eigenmodes with low frequencies are predominantly of circumferential nature; the stability of annular combustors is often governed by the onset of circumferential acoustic oscillations. To determine the influence of these circumferential acoustic modes on the dynamic flame behavior, a new single burner test rig was developed. The unique acoustic properties of the test rig allow the exposure of a single swirl burner to a two-dimensional acoustic field that resembles the circumferential mode in an annular combustor. Measurements were performed for axial as well as transversal excitation of the burner and the combination of both. To investigate the dynamic flame structure, phase-resolved flame images have been evaluated in terms of amplitude and phase distribution. Under transversal excitation, the flame structure becomes highly asymmetrical. A region of higher OH* intensity is generated in the combustion chamber, which rotates with the excitation frequency. From phase-resolved particle image velocimetry (PIV) measurements of the isothermal flow, it is concluded that the transversal excitation modulates the swirl generation leading to an asymmetrical velocity distribution in the burner nozzle and the combustion chamber. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Influence of transversal acoustic excitation of the burner approach flow on the flame structure [texte imprimé] / Martin Hauser, Auteur ; Manuel Lorenz, Auteur ; Thomas Sattelmayer, Auteur . - 2012 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 4 (Avril 2011) . - 08 p. Mots-clés : Acoustics  Electric  power  generation  Engines  Flames  Gas  turbines  Oscillations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Modern large gas turbines for power generation have multiple burners, which are distributed around the circumference of the engine and which generate flames in combustors of either annular or can-annular geometry. In both cases, considering only the axial modes has proven to be insufficient for the assessment of the thermoacoustic stability. An adequate analysis requires consideration of the circumferential acoustic coupling generated by the acoustic field in the upstream and downstream annuli and the open passages between the cans, respectively. As in annular combustors, the particularly critical eigenmodes with low frequencies are predominantly of circumferential nature; the stability of annular combustors is often governed by the onset of circumferential acoustic oscillations. To determine the influence of these circumferential acoustic modes on the dynamic flame behavior, a new single burner test rig was developed. The unique acoustic properties of the test rig allow the exposure of a single swirl burner to a two-dimensional acoustic field that resembles the circumferential mode in an annular combustor. Measurements were performed for axial as well as transversal excitation of the burner and the combination of both. To investigate the dynamic flame structure, phase-resolved flame images have been evaluated in terms of amplitude and phase distribution. Under transversal excitation, the flame structure becomes highly asymmetrical. A region of higher OH* intensity is generated in the combustion chamber, which rotates with the excitation frequency. From phase-resolved particle image velocimetry (PIV) measurements of the isothermal flow, it is concluded that the transversal excitation modulates the swirl generation leading to an asymmetrical velocity distribution in the burner nozzle and the combustion chamber. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]