1、ubstantially from the corresponding conditions for spillways constructed in the traditional configuration. Let usconsider these differences on the basis of the results of laboratory studies of the operational spillways of the Rogunskiihydroelectric plant (which includes an energy dissipation chamber
2、) and the spillway of the Teri hydraulic works (whichoperates with smooth dissipation of energy throughout the length of the tunnel).The initial design of the Rogunskii hydroelectric plant called for a chute as the terminus structure of the operationalspillway; it was intended that the flow rate at
3、the end of the chute was to reach 60 m/sec. Understandably, flow rates that arethis high entail adoption of special measures to protect the streamlined surfaces of the spillway from cavitation damage and the stream course from dangerous degradation. To meet this need, the Tashkent Hydroelectric Auth
4、ority, working with the Division of Hydrodynamic Research (now the Central Hydraulic Institute, Society of the Scientific Research Institute on the Economics of Construction), developed several alternative versions of spillway designs intended to dissipate a significant portion of the energy of the
5、flow within the spillway and to substantially reduce the flow rate in the tailrace tunnel and at the point where the flow is discharged into thestream course. In one of the versions that were considered, the bend in the turning segment that is part of the traditional configuration of a shaft spillwa
6、y was replaced by a tangential flow vortex generator. Similarly. vortex-type flow is created throughout the entire length of the tailrace segment. Hydraulic studies were performed on a model that simulated a shaft spillway at a scale of 1:50 and consisted of a shaft measuring 13 m in diameter and 14
7、8 m in height, a tangential vortex generating device, and a tailrace tunnel.The studies that were performed showed that in the shaft which delivers water to the flow rotation node, an intermediate water level is maintained when the flow rate is less than the design rate. This bench mark depends on t
8、he magnitude of the escapage discharge and the resistance of the spillway segment situated at a lower level . In the constructions that have been considered here, maximum (design) flow rates through the shaft are achieved when the shaft is flooded and there is no access to the air. In the model near
9、ly complete entrapment of air from the water surface occurred with intermediate water levels in the shaft; moreover, the lower the level of the water surface, the more the air restrained the water flow and transformed the flow into a rotation node (Fig. 7). Stable vortex-type flow with a peripheral water ring and internal gas-vapor core is formed beyond the tangential vortex generator. Due to asymmetric delivery of water into the vortex generator in the initial segments, the core of the flow is noncircular and situated away from the cen
