Seite - 1367 - in Book of Full Papers - Symposium Hydro Engineering

The change in head out of stepwise increased ejector ramp flow is shown in Fig. 2: A) Situation without ejector, where QT represents the turbine design flow B) Flood conditions, ejector operational, increase of the tail race water level C), D) Augmented flood condition, showing the shift of hydraulic surge downstream, increasing the useable head As a result of the momentum, it's clear to see the lowering of the tailrace water level at the draft tube outlet of the turbine, accompanied by an increase in the energy generating head, turbine flow and performance. A positive side effect of this special draft tube duct under the spillway or ejector ramp, is the elimination of sedimentation problems when flooding occurs. With regard to the operational safety of the plant, safe operation can be ensured even in the event of heavy surplus water or flooding, which nowadays leads to many power plants having to be disconnected from the grid. As described in Fig. 3 and Fig. 4 the main components of a typical ejector power plant are: (1) vertical Kaplan Turbine (2) curved suction tube (3) intake with horizontal screen (4) ejector gate (5) ejector ramp (6) turbine outlet Fig. 3 Plan view of a typical ejector power plant 1367