High-head spillway system with a countereddy energy dissipator

Abstract

1. The complexity of creating reliably operating high-head spillways is due to the need to protect structural elements of tunnel linings from the action of cavitation and dynamic loads and to dissipate the excess energy of the flow directly inside the tunnel. In connection with this the problem of developing new efficient designs is especially urgent. 2. The use of swirled flows in spillway systems makes it possible to improve considerably the cavitation and dynamic conditions in the passageway and to create reliably operating high-head spillways. 3. One of the most promising spillway systems with swirling of the flow is the countereddy spillway system proposed and tested at MISI, which permits actually at any head reducing the velocity of the through-going flow to values of 15–20 m/sec, which are safe in a cavitation and dynamic respect. These properties of the countereddy spillways are confirmed by the results of laboratory investigations. 4. Preliminary technicoeconomic calculations show that the introduction of such a system into hydrotechnical construction practice opens fundamentally new ways to design high-head spillways and effects a considerable saving of capital investments.