Author(s): Sun Shuangke; Chen Jie; Liu Zhiping; Guo Jun
Linked Author(s):
Keywords: Deep-level outlet; Aeration facility; Cavitation number; Sedimentabrasion
Abstract: The deep-level outlets of the Three Gorges Project (TGP) have two important hydraulic problems as following: The first is the problem of cavitation mitigation. Because the flow velocity in outlet exceeds 35m/s, aeration facility is used to protect the surface, the protecting range and its effect of aeration facility need to be evaluated correctly, and how to control the irregularity in construction work is of vital importance as well. The second is the problem of sediment abrasion. Because the operation mode of ¡°discharging the turbid flow and impounding the clear water¡± is to be adopted in TGP, the problem of the sediment abrasion on deep-level outlet is non-negligible. In this paper, based on the hydraulic model test, the protecting range and the effect of aeration facility are discussed, and the distribution of cavitation number along the flow passage also presented. Furthermore, the quantitative forecast of the sediment abrasion on deep-level outlets carried out by reviewing of the performance experience of some similar hydropower stations. The results show that the aeration facility is effective but the sediment abrasion is so serious that the designer, the builder, and the supervisor of TGP should pay grave attention to it.
Year: 2001