Research On The Shape Optimization Of Spillway And The Energy Dissipation Of Spilling Basin Of Bulongyan Hydropower Station

The research on the shape optimization of the water discharge structure and the reasonable choice of energy dissipation facilities are very important for the safety and economy of the water conservancy project.Combining the hydraulic design of water discharge structure in Bulongyan hydropower station,this paper explores and analyzes the optimization of spillway tunnel shape and the energy dissipation of stilling pool by physical model test and numerical simulation.Through the analysis of the physical model test results of the original program,the physical model test is applied to the shape study and optimization of the inlet section and aeration cavitation-alleviation facility;while the numerical simulation was applied to the study and optimization of the stilling pool type.After adjusting and optimizing the whole shape of the discharge structure,the physical model test was used to study the hydraulic characteristics in different flow conditions and the results show that the optimized water discharge structure achieved the expected effect.The main conclusions are as follows:(1)The discharge capacity and the flow state were improved by optimizing the shape of inlet section of spillway tunnel and the aeration cavitation-alleviation facility by physical model test according to the physical model test results of the original program,which avoid cavitation and cavitation damage on spillway tunnel.(2)After the comparison and analysis of the numerical simulation results and the results from physical model tests in the same working condition,the distribution law of flow state,water surface profile,current velocity,pressure and other hydraulic characteristics from the numerical simulation agree with the those from physical model tests which can be used for further optimization study on the stilling pool type.(3)The stilling pool of the original program does not form a complete hydraulic jump,and it doesn't use the energy dissipation mechanism to eliminate adverse kinetic energy through the hydraulic jump.Study and optimize the stilling pool by numerical simulation,choose the stilling pool whose sole plate reduces the aeration and sill with cantilever coping of +lateral as a recommendation,and then research the recommended stilling pool shape and original stilling pool shape by numerical simulation under the same working condition,compare the change law of the hydraulic characteristics to verify the superiority of the recommended program.(4)Study on the recommendation of stilling pool shape by numerical simulation under different flow conditions.Compare and analyze the law of change distribution of hydraulic characteristics such as the flow state,current velocity,pressure,turbulent energy and dissipation rate in the stilling pool,to show that under different flow conditions,the recommendation of stilling pool shape can achieve ideal energy dissipation and has good applicability.(5)Study on physical model test of the whole water discharge structure with optimized shape under different working conditions.Compare and analyze the flow state,water surface profile,pressure,and aerated elements other hydraulic characteristics of spillway tunnel section,stilling pool,and downstream river flow in different flow conditions,to show that the water discharge structure with optimized shape has achieved good results.