Page - 1387 - in Book of Full Papers - Symposium Hydro Engineering

REFERENCES [1] MOSONYI, E.: Wasserkraftwerke. Band 1 Niederdruckanlagen. Düsseldorf: VDI-Verlag, 1966. [2] SLISSKII, S. M.: Ejection into tailraces of hydropower plants. 1. A. Moskau: Gosudarstvennoe Energeticheskoe Izdatel’stvo, 1953. [3] FRITSCH, R., J ET AL.: Dissertation – Untersuchung der Ejektorwirkung bei vertikalen Kaplanturbinen, 2018 [TU Graz – Institute HFM – Prof. Dr. Jaberg] [4] SCHIFFER , J ET.AL.: NUMERICAL AND EXPERIMENTAL INVESTIGATION OF THE EJECTOR EFFECT APPLICABLE TO LOW HEAD VERTICAL KAPLAN TURBINES, Conference on Modelling Fluid Flow, At Budapest, Volume: The 16th International Conference on Fluid Flow Technologies [5] SCHIFFFER, J ET AL.: Experimentelle Untersuchung der Ejektorwirkung bei vertikalen Kaplan-TurbineN; In: WasserWirtschaft, 2015, 05, S33-39. SUMMARY In the course of this study we were able to scientifically determine increased outflow performance by utilizing an ejector, as we had indeed observed already in the pilot projects at Mühltalwehr/Alm and Stadtwehr Waidhofen/Ybbs. Comparative performance increases were also noted in our 1:10 scale model and in CFD simulation. In particular, we were able to demonstrate in the laboratory and in subsequent analyses that the efficiency of the ejector can be significantly increased by specific design measures between the draft tube and the run off, and also by changes in the position of the ejector sluice gate. The potential of the interaction of the head race water flow out of the draft tube together with the excess water from the ejector ramp represents the sum of the combination of effective drop height and turbine flow rate. First and foremost, the interaction of these two water volumes is accomplished as a result of a pressure drop, dependent on the momentum coming from the ejector, directly at the draft tube exit point. Increased performance of up to 35% is achievable, as compared to theoretical performance without the ejector in flood or excess water conditions. This breaks down to increased energy output of 7% - 10% at full load and 3% - 5% as an annual average. With consistent annual energy yield the development and head race design costs could be reduced by 5% – 10%, a substantial reduction in the construction and investment costs for new installations. 1387