Study On Hydraulic Characteristics Of Spillway Sluice Of The Qilin Temple Hydropower Station

In recent years,with the rapid development of water conservancy projects,there is an increasing demand for small and medium-sized hydropower stations and low-head flood discharge gates in the southwest and northwest valleys of China,which also highlights a series of engineering safety problems: for example,unreasonable design of hydraulic structures leads to insufficient flood discharge capacity,insufficient energy dissipation of flood discharge structures leads to excessive impact pressure of the stilling basin resulting in damage to the stilling basin floor,pulsating pressure leads to resonance of buildings,and downstream river channels and parts on both banks are severely scoured.Therefore,in the construction of hydropower projects,according to the specific location of the project and its own characteristics,reasonable layout of flood discharge buildings and optimization of the shape of flood discharge buildings are of great significance to ensure the safe operation of the whole hub project and bring into play its benefits.At present,the main research methods of fluid dynamics are theoretical analysis,experiment and numerical simulation.Simple theoretical analysis is difficult to get a good combination with practice.Although physical test is the most common solution in engineering,it has many problems,such as long cycle and high cost.The numerical simulation method can combine theory with practice,and has the advantages of low cost,fast speed and complete data information.At present,numerical simulation has become one of the important supplementary means of physical model tests.In this paper,the spillway gate of Bailong River Qilin Temple Hydropower Station is taken as the main research object.Through physical model tests,the hydraulic characteristics of the spillway building are studied experimentally.The hydraulic characteristics of the spillway gate chamber and stilling basin area and the fluctuating pressure in the middle line of stilling basin floor are simulated numerically in three dimensions.The following research results are obtained:(1)Through the analysis of model test results,the measured values and distribution laws of hydraulic elements such as discharge capacity,water surface line,sluice chamber pressure,stilling basin dynamic water pressure and flow pattern of the design scheme are obtained,and the rationality of the design scheme is demonstrated.(2)By using RNG Reynolds Average Navier-Stokes method and VOF free level tracking method,the hydraulic characteristics of flood discharge sluice are simulated in three dimensions.The results are in good agreement with the model test,which shows that the numerical simulation,as a supplementary means of model test,has good effect.(3)Through large eddy simulation of fluctuating pressure on the middle line of stilling basin bottom plate,the characteristic parameters of fluctuating pressure,such as time mean value,fluctuating pressure intensity,fluctuating pressure amplitude characteristic,probability density distribution and power spectrum density,are obtained.The comparison and analysis with the results of physical model test show that the large eddy numerical simulation method is reliable for studying fluctuating pressure of stilling basin bottom plate.