Documents disponibles écrits par cet auteur

Stall inception, evolution and control in a low speed axial fan with variable pitch in motion / Stefano Bianchi in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 134 N° 4 (Avril 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 4 (Avril 2012) . - 10 p. Titre : Stall inception, evolution and control in a low speed axial fan with variable pitch in motion Type de document : texte imprimé Auteurs : Stefano Bianchi, Auteur ; Alessandro Corsini, Auteur ; Luca Mazzucco, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Blades  Fans  Flow  instability  Probes  Rotors  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Obtaining the right pitch in turbomachinery blading is crucial to efficient and successful operations. Engineers adjust the rotor's pitch angle to control the production or absorption of power. Even for low speed fans this is a promising tool. This paper focuses on the inception and the evolution of the flow instabilities in the tip region which drive the stall onset in low speed axial fans. The authors conducted an experimental study to investigate the inception patterns of rotating stall evolution at different rotor blade stagger-angle settings with the aim of speculating on stable operating margin. The authors drove the fan to stall at the design stagger-angle setting and then operated the variable pitch mechanism in order to recover the unstable operation. They measured pressure fluctuations in the tip region of the low-speed axial-flow fan fitted with a variable pitch in motion mechanism, with flush mounted probes. The authors studied the flow mechanisms for spike and modal stall inceptions in this low-speed axial-flow fan which showed relatively small tip clearance. The authors cross-correlated the pressure fluctuations and analyzed the cross-spectra in order to clarify blade pitch, end wall flow, and tip-leakage flow influences on stall inception during the transient at the rotor blades' different stagger-angle settings. The authors observed a rotating instability near the maximum pressure-rise point at both design and low stagger-angle settings. The stall inception patterns were a spike type at the design stagger-angle setting as a result of the interaction between the incoming flow, tip-leakage flow and end wall backflow. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000004 [...] [article] Stall inception, evolution and control in a low speed axial fan with variable pitch in motion [texte imprimé] / Stefano Bianchi, Auteur ; Alessandro Corsini, Auteur ; Luca Mazzucco, Auteur . - 2012 . - 10 p. Génie mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 4 (Avril 2012) . - 10 p. Mots-clés : Blades  Fans  Flow  instability  Probes  Rotors  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Obtaining the right pitch in turbomachinery blading is crucial to efficient and successful operations. Engineers adjust the rotor's pitch angle to control the production or absorption of power. Even for low speed fans this is a promising tool. This paper focuses on the inception and the evolution of the flow instabilities in the tip region which drive the stall onset in low speed axial fans. The authors conducted an experimental study to investigate the inception patterns of rotating stall evolution at different rotor blade stagger-angle settings with the aim of speculating on stable operating margin. The authors drove the fan to stall at the design stagger-angle setting and then operated the variable pitch mechanism in order to recover the unstable operation. They measured pressure fluctuations in the tip region of the low-speed axial-flow fan fitted with a variable pitch in motion mechanism, with flush mounted probes. The authors studied the flow mechanisms for spike and modal stall inceptions in this low-speed axial-flow fan which showed relatively small tip clearance. The authors cross-correlated the pressure fluctuations and analyzed the cross-spectra in order to clarify blade pitch, end wall flow, and tip-leakage flow influences on stall inception during the transient at the rotor blades' different stagger-angle settings. The authors observed a rotating instability near the maximum pressure-rise point at both design and low stagger-angle settings. The stall inception patterns were a spike type at the design stagger-angle setting as a result of the interaction between the incoming flow, tip-leakage flow and end wall backflow. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000004 [...]

Stall warning in a low-speed axial fan by visualization of sound signals / Anthony G. Sheard 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) . - 10 p. Titre : Stall warning in a low-speed axial fan by visualization of sound signals Type de document : texte imprimé Auteurs : Anthony G. Sheard, Auteur ; Alessandro Corsini, Auteur ; Stefano Bianchi, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aerodynamics  Failure  (mechanical)  Fans  Flow  visualisation  Risk  analysis  Waveform  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This study describes the development of a novel stall-detection methodology for low-speed axial-flow fans. Because aerodynamic stall is a major potential cause of mechanical failure in axial fans, effective stall-detection techniques have had wide application for many years. However, aerodynamic stall does not always result in mechanical failure. A subsonic fan can sometimes operate at low speeds in an aerodynamically stalled condition without incurring mechanical failure. To differentiate between aerodynamic stall conditions that constitute a mechanical risk and those that do not, the stall-detection methodology in the present study utilizes a symmetrized dot pattern (SDP) technique that is capable of differentiating between stall conditions. This paper describes a stall-detections criterion based on a SDP visual waveform analysis and develops a stall-warning methodology based on that analysis. This study presents an analysis of measured acoustic and structural data across nine aerodynamic operating conditions represented in a 3×3 matrix. The matrix is a combination of (i) three speeds (full-, half-, and quarter-speed) and (ii) three operational states (stable operation, incipient stall, and rotating stall). The matrix of SDPs and structural data are used to differentiate critical stall conditions (those that will lead to mechanical failure of the fan) from noncritical ones (those that will not result in mechanical failure), thus providing a basis for an intelligent stall-warning methodology. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Stall warning in a low-speed axial fan by visualization of sound signals [texte imprimé] / Anthony G. Sheard, Auteur ; Alessandro Corsini, Auteur ; Stefano Bianchi, Auteur . - 2012 . - 10 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) . - 10 p. Mots-clés : Aerodynamics  Failure  (mechanical)  Fans  Flow  visualisation  Risk  analysis  Waveform  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This study describes the development of a novel stall-detection methodology for low-speed axial-flow fans. Because aerodynamic stall is a major potential cause of mechanical failure in axial fans, effective stall-detection techniques have had wide application for many years. However, aerodynamic stall does not always result in mechanical failure. A subsonic fan can sometimes operate at low speeds in an aerodynamically stalled condition without incurring mechanical failure. To differentiate between aerodynamic stall conditions that constitute a mechanical risk and those that do not, the stall-detection methodology in the present study utilizes a symmetrized dot pattern (SDP) technique that is capable of differentiating between stall conditions. This paper describes a stall-detections criterion based on a SDP visual waveform analysis and develops a stall-warning methodology based on that analysis. This study presents an analysis of measured acoustic and structural data across nine aerodynamic operating conditions represented in a 3×3 matrix. The matrix is a combination of (i) three speeds (full-, half-, and quarter-speed) and (ii) three operational states (stable operation, incipient stall, and rotating stall). The matrix of SDPs and structural data are used to differentiate critical stall conditions (those that will lead to mechanical failure of the fan) from noncritical ones (those that will not result in mechanical failure), thus providing a basis for an intelligent stall-warning methodology. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]