High-head spillway with swirling of the flow in the outlet section

Conclusions

• 1. A high-head spillway with swirling of the flow in the outlet section has economic, layout, and operational advantages. The cost of the proposed spillway — its main route, length, and cross-sectional area — is the same as for an ordinary spillway, since it is determined by the requirement of diverting the flow at low heads around the retaining structures of the hydropower development under construction. However, the cost of the entire development with the proposed spillways is less, since it is not required to construct special energy dissipators of the flow at the spillway exist, which are necessary for ordinary spillways. Energy dissipation is accomplished inside the proposed spillway.

• 2. For the spillway it is not required to develop and master new complex flow-swirling hydromechanical equipment. It is specially intended to use ordinary, simple vertical-lift and radial gates whose manufacture, assembly, and operation have long been mastered, operating in a free regime normal for them with regulation of the discharge and passage of trash.

• 3. The spillway does not require a long shutdown for converting from a diversion regime to a service regime, since the gates can be installed during construction or discharge of the construction flow through the spillway as a consequence of locating the gates on branches at a certain distance from its route.

• 4. In the case when the gate chambers of the spillway (usually two) are located on different branches with the provision of counterswirling of the flow, the length of the outlet section of the spillway can be reduced to 6 diameters, which leads to convenient layouts under mountainous conditions and in the case of small lengths of the spillways, for example, in the lower parts of gravity and arch dams.