A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Kurzfassung Bei neuesten Entwicklungen von Pumpspeicherkraftwerken werden Peltonturbinen im permanenten Gegendruckbetrieb eingesetzt. Für den sicheren und wirtschaftlichen Betrieb ist dabei die Kenntnis der erforderlichen Länge zur Luftrückgewinnung im Freispiegel — Unterwasserkanal der Turbine erforderlich. Im Beitrag werden Ergebnisse grundlegender hydraulischer Modellversuche der hydrodynamischen Prozesse im Turbinengehäuse und Unterwasserkanal sowie Versuche zur bestimmung der Steiggeschwindigkeit von Luft — Blasenschwärmen vorgestdlt. Messergebnisse der Luftkonzentrationen und Fließgeschwindigkeiten in Unterwasserkanälen von drei Großanlagen in Österreich werden präsentiert.
Summary The deregulated electricity market in Europe opens new potential for the construction of pumped storage hydropower plants. Optimum turbine efficiency under high head conditions for the various operation modes is achieved by the use of Pelton turbines. In order to reduce the shaft length between the storage pump and pelton runner in the power cavern (or powerhouse), it is possible to place the Pelton runner below the water level of the lower reservoir. This kind of arrangement requires that the water level below the runner is pressed down by means of overpressure. When the water — flowing out from the nozzles — hits the runner buckets and falls down into the tailwater channel, considerable amounts of air are dragged into the water. This air must be separated from the fluid before the flow reaches the pressurized conduit system. In case that the de-aeration length of the tailwater channel is too small, air is conveyed towards the reservoir. In order to maintain air volume inhte tailwater channel, additional air has to be pumped into the tailwater channel which may cause disadvantageous technical and economical situations for the whole system. The paper describes the general flow pattern in tailwater channels of Pelton turbines starting from the runner bucket. General effects of overpressure on the de-aeration process is discussed. Results of prototype measurements for air-water velocities and void fraction for three tailwater channels are presented. An extension of an existing formula for the de-aeration length is presented.
Kurzfassung Bei neuesten Entwicklungen von Pumpspeicherkraftwerken werden Peltonturbinen im permanenten Gegendruckbetrieb eingesetzt. Für den sicheren und wirtschaftlichen Betrieb ist dabei die Kenntnis der erforderlichen Länge zur Luftrückgewinnung im Freispiegel — Unterwasserkanal der Turbine erforderlich. Im Beitrag werden Ergebnisse grundlegender hydraulischer Modellversuche der hydrodynamischen Prozesse im Turbinengehäuse und Unterwasserkanal sowie Versuche zur bestimmung der Steiggeschwindigkeit von Luft — Blasenschwärmen vorgestdlt. Messergebnisse der Luftkonzentrationen und Fließgeschwindigkeiten in Unterwasserkanälen von drei Großanlagen in Österreich werden präsentiert.
Summary The deregulated electricity market in Europe opens new potential for the construction of pumped storage hydropower plants. Optimum turbine efficiency under high head conditions for the various operation modes is achieved by the use of Pelton turbines. In order to reduce the shaft length between the storage pump and pelton runner in the power cavern (or powerhouse), it is possible to place the Pelton runner below the water level of the lower reservoir. This kind of arrangement requires that the water level below the runner is pressed down by means of overpressure. When the water — flowing out from the nozzles — hits the runner buckets and falls down into the tailwater channel, considerable amounts of air are dragged into the water. This air must be separated from the fluid before the flow reaches the pressurized conduit system. In case that the de-aeration length of the tailwater channel is too small, air is conveyed towards the reservoir. In order to maintain air volume inhte tailwater channel, additional air has to be pumped into the tailwater channel which may cause disadvantageous technical and economical situations for the whole system. The paper describes the general flow pattern in tailwater channels of Pelton turbines starting from the runner bucket. General effects of overpressure on the de-aeration process is discussed. Results of prototype measurements for air-water velocities and void fraction for three tailwater channels are presented. An extension of an existing formula for the de-aeration length is presented.
Entgasung von Wasser-Luft-Gemischen in Unterwasserkanälen von Pelton-Wasserkraftanlagen
Spezielle anwendung in pumpspeicherkraftwerken de-aeration of air-water flows in tailwater channels of Pelton turbines special application in pumped storage schemes
Österreichische Wasser- und Abfallwirtschaft ; 57 ; 167-175
2005-11-01
9 pages
Article (Journal)
Electronic Resource
German
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