Hydraulic Model Test on Diversion Structures of Gongguoqiao Hydropower Station during Construction

Based on hydrologic data and diversion structure arrangement of Gongguoqiao hydropower station during construction, the hydraulic model on diversion structures is built according to similarity principle. Then the hydraulic characteristic and its flow model were studied by hydraulic model test. Hydraulic characteristic and flow pattern for the diversion tunnel and dam gap combined discharge were studied subsequently in this paper. The study results show that half pressure flow state is formed in the diversion tunnel when quantity of flow is greater than 3500m3/s. That submerged flow is formed exactly in the inlet of diversion tunnel when quantity of flow is 5000m3/s. Three aeration segments are formed in the top of diversion tunnel when quantity of flow is greater than 6580m3/s. The study results also show non-interpenetrated turbulence is formed intermittently in the right bank of inlet for diversion tunnel when quantity of flow is greater than 7710m3/s, and the flow over the upstream cofferdam is near the submerged hydraulic jump.