Model Test And Numerical Simulation For Joint Energy Dissipation In Shared Stilling Basin Of Bottom Outlets And Surface Outlets

Over the years,the construction of hydropower has flourished and many hydropower stations have been built on the river.From the upstream to the downstream,the potential energy of flow turns into kinetic energy.If the kinetic energy isn’t dissipated in time,it will threaten the safety of the dam and the downstream.Underflow energy dissipation is the earliest energy dissipation used in the water conservancy project.It is suitable for low-head hydropower station and can adapt many kinds of tailwater.With the development of hydroelectric engineering,underflow energy dissipation is researched more and different efficient energy dissipation workers adapted for many conditions are invented.Practice shows that joint energy dissipation in shared stilling basin of bottom outlets and surface outlets not only inherits the characteristics of the underflow energy dissipation,but also has new features.This way of energy dissipation helps the high-speed drop jet of the bottom outlet diffuse horizontally,collide with the water of surface outlet,produce many bubbles and improve the energy dissipation rate.There are three main methods of fluid mechanics:theoretical analysis,physical model test and numerical simulation.However,due to the complexity of the turbulence and the boundary conditions,the hydraulic characteristics of the mix flow with different hydraulic characteristics can not be analyzed by the theory.Based on the previous study of the underflow energy dissipation,relying on the Lianhuasi reservoir,using model test and numerical Simulation,this paper makes a deeper research to study the hydraulic characteristics of the mix flow of bottom outlet and surface outlet.(1)Based on the characteristics of the Lianhuasi reservoir,the hydraulic physical model is established.The velocity,pressure and energy dissipation rate of the power pool were studied for the original scheme and two optimization schemes.Contrast the variability of these hydraulics parameters for each scheme,and determine the optimal scheme.(2)Use the RNG two-equation turbulence model and VOF method to simulate the flow of the stilling pool and study the velocity and pressure distribution in the energy dissipation pool.Then use the physical model to verify the numerical simulation,but also verify the optimal scheme.(3)In order to study the influence of the splitter wall on the velocity and pressure in the stilling basin,the original scheme and the optimization scheme are further studied by means of numerical simulation.The change of the velocity distribution in the horizontal plane profile is studied,and the variation law of the transverse diffusion angle of the bottom outlet is preliminarily proposed.(4)Summarize this paper,analyze what is not studied comprehensively and come up with some ideas that can solve the problems in the future.The methods and results of this paper can provide some reference for future engineering design and research on hydraulic hydraulics.