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Effects of blade wrap angle influencing a pump as turbine / Sun-Sheng Yang in Transactions of the ASME . Journal of fluids engineering, Vol. 134 N° 6 (Juin 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 6 (Juin 2012) . - 08 p. Titre : Effects of blade wrap angle influencing a pump as turbine Type de document : texte imprimé Auteurs : Sun-Sheng Yang, Auteur ; Fan-Yu Kong, Auteur ; Hao Chen, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : pump  as  turbine;  blade  wrap  angle;  numerical  research;  performance  analysis;  hydraulic  loss  distribution Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A pump is not ideally designed to operate as a turbine. To improve the efficiency of a pump as turbine (PAT), the redesign of the PAT, according to the flow of the turbine, is required. The blade wrap angle is one of the main geometric parameters in impeller design. Therefore, an investigation into the blade wrap angle to the PAT's influence can be useful. In order to understand blade wrap angle to the influence of the PAT, this paper numerically investigated three different specific speeds of PATs with different blade wrap angles. The validity of numerical simulation was first confirmed through a comparison between numerical and experimental results. The performance change of the PATs with the blade wrap angle was acquired. A detailed hydraulic loss distribution and a theoretical analysis were performed to investigate the reasons for performance changes caused by the blade wrap angle. The results show that there is an optimal blade wrap angle for a PAT to achieve the highest efficiency and the optimal blade wrap angle decreases with an increasing specific speed. A performance analysis shows the PAT's flow versus pressure head (Q-H) and flow versus generated shaft power (Q-P) curves are lowered with the decrease of the blade wrap angle. The hydraulic loss distribution and theoretical analysis illustrate that it is the decrease of hydraulic loss within the impeller, together with the decrease of the theoretical head, that results in the performance decrease. The decrease of hydraulic loss within the impeller is attributed to the shortened impeller blade passage and the reduced velocity gradient within the impeller flow channel. With the decrease of the blade wrap angle, the slip factor of the PAT's impeller is decreased; therefore, its theoretical head is also decreased. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000006 [...] [article] Effects of blade wrap angle influencing a pump as turbine [texte imprimé] / Sun-Sheng Yang, Auteur ; Fan-Yu Kong, Auteur ; Hao Chen, Auteur . - 2012 . - 08 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 6 (Juin 2012) . - 08 p. Mots-clés : pump  as  turbine;  blade  wrap  angle;  numerical  research;  performance  analysis;  hydraulic  loss  distribution Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A pump is not ideally designed to operate as a turbine. To improve the efficiency of a pump as turbine (PAT), the redesign of the PAT, according to the flow of the turbine, is required. The blade wrap angle is one of the main geometric parameters in impeller design. Therefore, an investigation into the blade wrap angle to the PAT's influence can be useful. In order to understand blade wrap angle to the influence of the PAT, this paper numerically investigated three different specific speeds of PATs with different blade wrap angles. The validity of numerical simulation was first confirmed through a comparison between numerical and experimental results. The performance change of the PATs with the blade wrap angle was acquired. A detailed hydraulic loss distribution and a theoretical analysis were performed to investigate the reasons for performance changes caused by the blade wrap angle. The results show that there is an optimal blade wrap angle for a PAT to achieve the highest efficiency and the optimal blade wrap angle decreases with an increasing specific speed. A performance analysis shows the PAT's flow versus pressure head (Q-H) and flow versus generated shaft power (Q-P) curves are lowered with the decrease of the blade wrap angle. The hydraulic loss distribution and theoretical analysis illustrate that it is the decrease of hydraulic loss within the impeller, together with the decrease of the theoretical head, that results in the performance decrease. The decrease of hydraulic loss within the impeller is attributed to the shortened impeller blade passage and the reduced velocity gradient within the impeller flow channel. With the decrease of the blade wrap angle, the slip factor of the PAT's impeller is decreased; therefore, its theoretical head is also decreased. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000006 [...]

Influence of blade number on the performance and pressure pulsations in a pump used as a turbine / Sun-Sheng Yang in Transactions of the ASME . Journal of fluids engineering, Vol. 134 N° 12 (Décembre 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 12 (Décembre 2012) . - 10 p. Titre : Influence of blade number on the performance and pressure pulsations in a pump used as a turbine Type de document : texte imprimé Auteurs : Sun-Sheng Yang, Auteur ; Fan-Yu Kong, Auteur ; Xiao-Yun Qu, Auteur Année de publication : 2013 Article en page(s) : 10 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : pressure;  flow  (dynamics);  impellers;  pumps;  turbines;  blades Résumé : The rotor-stator interaction of a rotating impeller and a stationary volute could cause strong pressure pulsations and generate flow induced noise and vibration in a pump used as a turbine (PAT). Blade number is one of the main geometric parameters of the impeller. In this paper, a numerical investigation of the PAT’s unsteady pressure field with different blade numbers was performed. The accuracy of global performance prediction by computational fluid dynamics (CFD) was first verified through comparison between numerical and experimental results. Unsteady pressure fields of the PAT with different blade numbers were simulated, and the pulsations were extracted at various locations covering the PAT’s three main hydraulic parts. A detailed analysis of the unsteady pressure field distributions within the PAT’s control volume and comparison of unsteady pressure difference caused by the increase of blade number were performed. The transient flow results provided the unsteady pressure distribution within PAT and showed that increasing the blade number could effectively reduce the amplitude of pressure pulsations. Finally, unsteady pressure field tests were performed and some unsteady results obtained by unsteady field analysis were validated. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...] [article] Influence of blade number on the performance and pressure pulsations in a pump used as a turbine [texte imprimé] / Sun-Sheng Yang, Auteur ; Fan-Yu Kong, Auteur ; Xiao-Yun Qu, Auteur . - 2013 . - 10 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 12 (Décembre 2012) . - 10 p. Mots-clés : pressure;  flow  (dynamics);  impellers;  pumps;  turbines;  blades Résumé : The rotor-stator interaction of a rotating impeller and a stationary volute could cause strong pressure pulsations and generate flow induced noise and vibration in a pump used as a turbine (PAT). Blade number is one of the main geometric parameters of the impeller. In this paper, a numerical investigation of the PAT’s unsteady pressure field with different blade numbers was performed. The accuracy of global performance prediction by computational fluid dynamics (CFD) was first verified through comparison between numerical and experimental results. Unsteady pressure fields of the PAT with different blade numbers were simulated, and the pulsations were extracted at various locations covering the PAT’s three main hydraulic parts. A detailed analysis of the unsteady pressure field distributions within the PAT’s control volume and comparison of unsteady pressure difference caused by the increase of blade number were performed. The transient flow results provided the unsteady pressure distribution within PAT and showed that increasing the blade number could effectively reduce the amplitude of pressure pulsations. Finally, unsteady pressure field tests were performed and some unsteady results obtained by unsteady field analysis were validated. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...]