Documents disponibles écrits par cet auteur

Modeling and model updating of torsional behavior of an industrial steam turbo generator / Roberto Ricci in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 7 (Juillet 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 7 (Juillet 2010) . - 07 p. Titre : Modeling and model updating of torsional behavior of an industrial steam turbo generator Type de document : texte imprimé Auteurs : Roberto Ricci, Auteur ; Paolo Pennacchi, Auteur ; Emanuel Pesatori, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Boilers  Eigenvalues  and  eigenfunctions  Torsion  Turbogenerators  Vibrations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The methods employed to perform rotordynamics calculations of industrial machines are rather standard and usually allow forecasting the dynamic behavior of the considered machines. Anyhow, in some cases, in order to obtain high level of accuracy, the model has to be updated to fit experimental results, and standard modeling methods have to be improved. In this paper, the updating of the torsional model of a steam turbogenerator is presented. In order to fit the eigenfrequencies calculated using the standard model and the natural frequencies measured on-field, a modeling improvement is proposed, considering partially the dynamics of the components usually modeled as rigid disks. The proposed method has also the aim to preserve the physical meaning of the model. Finally, the new model is updated, and a very good fitting is obtained between eigenfrequencies and experimental natural frequencies. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000007 [...] [article] Modeling and model updating of torsional behavior of an industrial steam turbo generator [texte imprimé] / Roberto Ricci, Auteur ; Paolo Pennacchi, Auteur ; Emanuel Pesatori, Auteur . - 2011 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 7 (Juillet 2010) . - 07 p. Mots-clés : Boilers  Eigenvalues  and  eigenfunctions  Torsion  Turbogenerators  Vibrations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The methods employed to perform rotordynamics calculations of industrial machines are rather standard and usually allow forecasting the dynamic behavior of the considered machines. Anyhow, in some cases, in order to obtain high level of accuracy, the model has to be updated to fit experimental results, and standard modeling methods have to be improved. In this paper, the updating of the torsional model of a steam turbogenerator is presented. In order to fit the eigenfrequencies calculated using the standard model and the natural frequencies measured on-field, a modeling improvement is proposed, considering partially the dynamics of the components usually modeled as rigid disks. The proposed method has also the aim to preserve the physical meaning of the model. Finally, the new model is updated, and a very good fitting is obtained between eigenfrequencies and experimental natural frequencies. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000007 [...]

Torsional vibrations caused by geared coupling in a shaft train driven by a steam turbine / Paolo Pennacchi in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 1 (Janvier 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 1 (Janvier 2011) . - 08 p. Titre : Torsional vibrations caused by geared coupling in a shaft train driven by a steam turbine Type de document : texte imprimé Auteurs : Paolo Pennacchi, Auteur ; Andrea Vania, Auteur ; Franco Frattaroli, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Couplings  Shafts  Steam  turbines  Turbomachinery  Vibrations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Rotating machines that include geared shaft-trains can be affected by a dynamic behavior that is influenced by coupling effects between lateral and torsional vibrations. These latter vibrations are rarely measured by means of permanent probes in industrial machines; therefore, these phenomena can be often pointed out only by detecting abnormal harmonic components in the frequency spectrum of the lateral vibrations measured during common monitoring activities. Then, the diagnosis of the occurrence of coupling effects between torsional and lateral vibrations can be supported by the results provided by model-based techniques. In this paper, the results of the analysis of the dynamic behavior of a small power unit that was affected by abnormal lateral vibrations caused by the excitation of torsional normal modes of the geared shaft-train are shown and discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Torsional vibrations caused by geared coupling in a shaft train driven by a steam turbine [texte imprimé] / Paolo Pennacchi, Auteur ; Andrea Vania, Auteur ; Franco Frattaroli, 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° 1 (Janvier 2011) . - 08 p. Mots-clés : Couplings  Shafts  Steam  turbines  Turbomachinery  Vibrations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Rotating machines that include geared shaft-trains can be affected by a dynamic behavior that is influenced by coupling effects between lateral and torsional vibrations. These latter vibrations are rarely measured by means of permanent probes in industrial machines; therefore, these phenomena can be often pointed out only by detecting abnormal harmonic components in the frequency spectrum of the lateral vibrations measured during common monitoring activities. Then, the diagnosis of the occurrence of coupling effects between torsional and lateral vibrations can be supported by the results provided by model-based techniques. In this paper, the results of the analysis of the dynamic behavior of a small power unit that was affected by abnormal lateral vibrations caused by the excitation of torsional normal modes of the geared shaft-train are shown and discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]