A methodology for on the fly acoustic characterization of the feeding line impedances in a turbulent swirled combustor / Lamraoui, A. in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 1 (Janvier 2011)  

Public ISBD [article]  inTransactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 1 (Janvier 2011) . - 07 p. Titre : A methodology for on the fly acoustic characterization of the feeding line impedances in a turbulent swirled combustor Type de document : texte imprimé Auteurs : Lamraoui, A., Auteur ; F. Richecoeur, Auteur ; Thierry Schuller, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Acoustic impedance Combustion equipment Mach number Microphones Swirling flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A methodology is proposed to determine on the fly the acoustic impedances at the boundaries of a combustor under operation and without the need for an external forcing device. The methodology is applied hereby to obtain the reflection coefficients of the air and fuel feeding lines supplying a swirled combustor operating in lean conditions and featuring an unstable regime. It is based on a three-microphone technique and uses the combustion roar noise inside the chamber to get estimates of the boundary impedances in the low frequency limit. Conditions under which this method yields reliable results for the reflection coefficient are examined, and a criterion based on the coherence between microphone signals is proposed to determine the frequency bandwidth for impedance reconstruction. The method also takes into account the flow Mach number in the supplying pipes, which can be non-negligible because of their reduced diameter. The technique is validated against data obtained in a dedicated impedance measurement setup equipped with a high-efficiency loudspeaker. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] A methodology for on the fly acoustic characterization of the feeding line impedances in a turbulent swirled combustor [texte imprimé] / Lamraoui, A., Auteur ; F. Richecoeur, Auteur ; Thierry Schuller, Auteur . - 2012 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 1 (Janvier 2011) . - 07 p. Mots-clés : Acoustic impedance Combustion equipment Mach number Microphones Swirling flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A methodology is proposed to determine on the fly the acoustic impedances at the boundaries of a combustor under operation and without the need for an external forcing device. The methodology is applied hereby to obtain the reflection coefficients of the air and fuel feeding lines supplying a swirled combustor operating in lean conditions and featuring an unstable regime. It is based on a three-microphone technique and uses the combustion roar noise inside the chamber to get estimates of the boundary impedances in the low frequency limit. Conditions under which this method yields reliable results for the reflection coefficient are examined, and a criterion based on the coherence between microphone signals is proposed to determine the frequency bandwidth for impedance reconstruction. The method also takes into account the flow Mach number in the supplying pipes, which can be non-negligible because of their reduced diameter. The technique is validated against data obtained in a dedicated impedance measurement setup equipped with a high-efficiency loudspeaker. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

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