Research On Tailrace System Of Tunnel With Sloping Ceiling In Right Bank Underground Hydropower Station

According to the characteristic of Xiangjiaba Underground Hydropower Station at the right bank of Jinsha River, one alternative option that the tailrace tunnel with sloping ceiling is adopted has been studied comprehensively, by method of model test and numerical calculation. The results provide important warrantee for the engineering design and construction organizing. The paper consists of several chapters:Chapter 1 introduces the general situation of Xiangjiaba Hydropower Station. And the problem existed in the project arrangement on the right bank underground hydropower station is brought forward. By getting over the state of the art about the technique of the tailrace tunnel with sloping ceiling, the research contents and study ways and means are put forward, and the importance to research is explained.Chapter 2 introduces the working principle of the tailrace tunnel with sloping ceiling. And the design of body type, appliance condition and the numerical model for transient process are illuminated. The main point is to establish and analyze the numerical model, and to select a rational calculation model and method to simulate the o the free surface and pressurized flow.Chapter 3 introduces the research contents and the results of the model test about the Xiangjiaba tailrace tunnel with sloping ceiling. By the model test with model hydro turbine and generator units, on the condition of the steady flow, unsteady flow, and the flow state in the tailrace tunnel with sloping ceiling is understood. The large oscillation, small oscillation and hydraulic disturbance have been analyzed. It shows that the design of tailrace tunnel with sloping ceiling is suitable and provides a hard foundation for the project design.Chapter 4 shows the results of the numerical calculation. And the comparison between the numerical calculation and the model test illustrates that the two results are consistent. It verified the validity of the numerical model and the calculation method.Chapter 5 introduces several research results by several scientific research units. The research finding of the tailrace tunnel with sloping ceiling is summarized. The scope of application is discussed according to the practical engineering, and is has a good prospect.