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Dependency on runner geometry for reversible-pump turbine characteristics in turbine mode of operation / Grunde Olimstad 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) . - 09 p. Titre : Dependency on runner geometry for reversible-pump turbine characteristics in turbine mode of operation Type de document : texte imprimé Auteurs : Grunde Olimstad, Auteur ; Torbjørn Nielsen, Auteur ; Bjarne Børresen, Auteur Année de publication : 2013 Article en page(s) : 09 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : rotation;  flow  (dynamics);  pump  turbines;  pumps;  turbines;  blades;  geometry;  shapes Résumé : Characteristics of a reversible-pump turbine have been measured with five different leading edge profiles in turbine mode. These profiles varied the inlet blade angle and the radius of curvature. Further geometry parameters have been investigated through numerical simulations. The pump turbine tested has much steeper flow-speed characteristics than a comparable Francis turbine. The most obvious geometry difference is the inlet part of the runner blades, where the blade angle for the pump turbine is much smaller than for the Francis turbine. Two different blade angles have been tested on a physical model and computational fluid dynamics (CFD) simulations have been performed on four different angles. Both methods show that a smaller blade angle gives less steep characteristics in turbine mode, whereas the measured s-shape in turbine brake- and turbine pumping mode gets more exaggerated. Long-radius leading edges result in less steep characteristics. The unstable pump turbine characteristics are in the literature shown to be a result of vortex formation in the runner and guide vane channels. A leading edge with longer curvature radius moves the formation of vortices towards higher speed of rotation. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...] [article] Dependency on runner geometry for reversible-pump turbine characteristics in turbine mode of operation [texte imprimé] / Grunde Olimstad, Auteur ; Torbjørn Nielsen, Auteur ; Bjarne Børresen, Auteur . - 2013 . - 09 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 12 (Décembre 2012) . - 09 p. Mots-clés : rotation;  flow  (dynamics);  pump  turbines;  pumps;  turbines;  blades;  geometry;  shapes Résumé : Characteristics of a reversible-pump turbine have been measured with five different leading edge profiles in turbine mode. These profiles varied the inlet blade angle and the radius of curvature. Further geometry parameters have been investigated through numerical simulations. The pump turbine tested has much steeper flow-speed characteristics than a comparable Francis turbine. The most obvious geometry difference is the inlet part of the runner blades, where the blade angle for the pump turbine is much smaller than for the Francis turbine. Two different blade angles have been tested on a physical model and computational fluid dynamics (CFD) simulations have been performed on four different angles. Both methods show that a smaller blade angle gives less steep characteristics in turbine mode, whereas the measured s-shape in turbine brake- and turbine pumping mode gets more exaggerated. Long-radius leading edges result in less steep characteristics. The unstable pump turbine characteristics are in the literature shown to be a result of vortex formation in the runner and guide vane channels. A leading edge with longer curvature radius moves the formation of vortices towards higher speed of rotation. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...]