Author(s): Serife Yurdagul Kumcu; Mehmet Ali Kokpinar
Linked Author(s): Mehmet Ali Kökpinar
Keywords: Ilisu Dam; Spillway aerators; Bottom outlet; Water jet; Diversion tunnel
Abstract: Ilisu Dam and Hydroelectric Power Plant (HEPP) are under construction on the Tigris River on the south east of the Turkey. During the construction stage, Tigris River has been diverted by 3 concrete-lined diversion tunnels each having a diameter of DT1 = DT2 = DT3 = 12 m and the lengths of L1 = 1064 m, L2 = 1016. 1 m and L3 = 915. 3 m. During the last stage of the construction, it was planned that DT2 diversion channel would be used as the dam bottom outlet structure. In the bottom outlet structure design, water is released from the intake structure to the bottom outlet by means of two slide gate valves as control structures. In this study, the valves’ performance and their rating curves for full and partial openings during the operation conditions are analyzed from an experimental point of view. The flow conditions, the water jet lengths at the downstream of the valves are also investigated in this paper along with the possibility of cavitation in the tunnel. Experimental studies showed that, during the maximum operation conditions (the reservoir water level, RWL = 520 m and the flow discharge, Q = 840 m3/s) of the bottom outlet, the maximum water jet trajectory was observed as Ljet = 40 m. The pressure measurements showed that, since the tunnel was not aerated enough cavitation was observed. As a consequence, and following a detailed experimental investigation that considered all the operational conditions, , the locations and the shapes of the aerators were redesigned. Finally, three aerators having diverters were added to diversion tunnel and their locations were at Km: 090, Km: 210 and Km: 330 as taking into account that slide gate valves were at Km: 000 (Kumcu, 2011).
Year: 2013