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Instabilities of nonreturn valves in low-speed air systems / Mark Potter in Transactions of the ASME . Journal of fluids engineering, Vol. 130 N° 12 (Décembre 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 12 (Décembre 2008) . - 8 p Titre : Instabilities of nonreturn valves in low-speed air systems Type de document : texte imprimé Auteurs : Mark Potter, Auteur ; Marko Bacic, Auteur ; Phil Ligrani, Auteur Année de publication : 2009 Article en page(s) : 8 p Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Flow  (Dynamics);  valves;  stability Résumé : Practical observations of the nonreturn valve wear in aero-engine cabin-bleed systems suggest that such valves are subject to unstable behavior. A theoretical model for the prediction of nonreturn valve instabilities in air systems is proposed and a nonlinear state-space model of the nonreturn valve and air volume interaction is derived from first principles. Experimental work is used to identify both the dynamic characteristics and the flow properties of the valve, which are used to identify the coefficients within the model. Through frequency analysis of valve oscillatory behavior, the levels of damping within the system are identified. Finally, using a local linearization of the state-space model an explicit mathematical prediction of valve stability is derived based on system parameters. These predictions are used to generate a map of the transition from stable to unstable system behavior for low-speed air flow, which is in excellent agreement with experimental data. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27349 [...] [article] Instabilities of nonreturn valves in low-speed air systems [texte imprimé] / Mark Potter, Auteur ; Marko Bacic, Auteur ; Phil Ligrani, Auteur . - 2009 . - 8 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 12 (Décembre 2008) . - 8 p Mots-clés : Flow  (Dynamics);  valves;  stability Résumé : Practical observations of the nonreturn valve wear in aero-engine cabin-bleed systems suggest that such valves are subject to unstable behavior. A theoretical model for the prediction of nonreturn valve instabilities in air systems is proposed and a nonlinear state-space model of the nonreturn valve and air volume interaction is derived from first principles. Experimental work is used to identify both the dynamic characteristics and the flow properties of the valve, which are used to identify the coefficients within the model. Through frequency analysis of valve oscillatory behavior, the levels of damping within the system are identified. Finally, using a local linearization of the state-space model an explicit mathematical prediction of valve stability is derived based on system parameters. These predictions are used to generate a map of the transition from stable to unstable system behavior for low-speed air flow, which is in excellent agreement with experimental data. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27349 [...]