Research on structure optimization of overflow orifices in Hydropower Station

Abstract

With the characteristics of large flood discharge and high water head, the flood discharge and energy dissipation structures of the dam body of A Hydropower Station are composed of overflow orifice, deep orifices, pond behind the dam and the second dam. In order to reduce the impact of the flood tongue on the cushion pond behind the dam, the method of stratified flow and air collision are adopted in the design of overflow orifice and deep orifice. The hydraulic model test is carried out to analyze body structure parameters such as diversion pier of overflow orifice, trajectory angle of outlet and so on, finally put forward the recommended structure design of overflow orifice. The model test showed that The setting of the diversion pier reduces the collision effect, therefore, it is not advisable to set the diversion pier. The structure of great differential drop and tongue without diversion pier are put forward, which can achieve the effect of layering the water tongue into the water, and colliding water tongue fully. The recommended structure can control the peak pressure of the cushion pond behind the dam within the allowable range.