Author(s): W. Richter; J. Schneider; G. Zenz; S. Kolb
Linked Author(s): Josef Schneider
Keywords: No Keywords
Abstract: Due to the increased requirements of hydro power plants concerning shifting times and increasing discharges an optimized surge tank design is still in development. The surge tank facility has three main benefits: the protection of the pressure tunnel from water hammer propagation, improved controllability and an enhanced mass oscillation behavior due to the needs of the electrical facilities. In the past decades surge tanks especially in Austria have become more and more sophisticated to fulfill technical as well as economical aspects. Therefore the design of chamber surge tanks has been adapted with throttles and overflows to use differential effects such as symmetrical or asymmetric hydraulic losses or column separation. In case of the downsurge process after filling the upper chamber the water column separates at a certain time at the overflow edge of the upper chamber. The water surface in the main shaft is dropping while water remains in the upper chamber. The remaining water plunges as a waterfall down the main shaft and entrains air bubbles by a jet into the water body at the level of the lower chamber. It is important to avoid an entering of air bubbles into to pressure tunnel. To check the functionality of a specific large surge tank facility a physical model test was carried out. In order of hybrid modeling additional investigations in terms of 3D-numerical calculations were tested and applied to the results of the physical model test. Here are introduced the investigations regarding the degassing process of a waterfall that entrains air bubbles into the lower chamber.
Year: 2012