Experimental Study On The Hydraulic Characteristics Of BSAM Reservoir Release Building And Its Energy Dissipation Method

A water conservancy hub is a complex composed of various structures built in rivers or channels in order to achieve the goal of benefiting and eliminating harms.The hub is composed of a variety of buildings,including water retaining structures,drainage structures,and water intake structures.And special buildings,among which the water retaining structure and the water discharge structure are the key parts of the hub,which ensure the safe operation of the water conservancy hub,the water retaining structure intercepts the river,and the water discharge structure undertakes the function of catharsis of the flood.After analyzing the causes of accidents in water conservancy complexes where accidents occurred in the past,it was found that accidents attributed to the problems of the discharge structures themselves accounted for a large proportion.Therefore,it is necessary to focus on the discharge capacity and energy dissipation of the discharge structures in the water control complex.Way to conduct research.This paper takes the Xinjiang BSAM reservoir project as the research object,builds a corresponding hydraulic model research platform,and carries out related research on the discharge structure to be constructed in the reservoir.The spillway tunnel is determined to be a deep spillway and a surface spillway due to different inlet elevations and layout methods.Due to the different inlet conditions,the two types of discharge structures are different in terms of operation mode,discharge capacity,and flow field in the tunnel.At the same time,they have similar hydraulic problems.The following research results have been obtained through this analysis and research:(1)The initial plan of the deep-hole spillway tunnel basically meets the needs of engineering application,and the discharge capacity of each working condition during the diversion period and the operation period meets the requirements.When the diversion degree is flooded,the flood discharge tunnel has alternate open and full flow phenomena,which requires special attention.Flood discharge during the operation period The water surface line in the tunnel stays high along the way,the flow velocity decreases accordingly,the bottom plate pressure gradually increases along the way,and the cavitation number increases along the way;as the flow velocity of the water flowing out of the gate is as high as 40m/s,in order to protect the safety of the flood discharge tunnel bottom plate,a total of two aeration reduction Erosion and decline can form a stable cavity.(2)The initial plan of the surface spillway has serious folding and flushing water flows and intersecting water fins,which do not meet the needs of engineering applications.Aiming at the design form of the spillway of this project with three holes and one slot,and the side wall gradually shrinking,it is planned to adopt additional installations after body type comparison and selection.The 1:20 slope adjustment section is designed to slow down the flow rate of the water in the tunnel and reduce the intensity of the bending water flow,and the effect of smooth flow is obvious.The discharge capacity of the spillway tunnel check and design conditions meet the requirements.The water flow velocity in the tunnel increases along with the decrease in elevation.The velocity at the upstream and downstream of the anti-arc section is basically stable at around 30m/s,and the water surface line is blocked in the adjustment section.It is high,and gradually decreases along the way into the Woqi section.After the flow rate is stable,the water surface remains stable.There is a small negative pressure at the top of the WES weir when the flow is discharged.The pressure change along the way is similar to the change of the water surface line;two aerated drop sills are arranged to effectively prevent the bottom plate from cavitation damage.(3)The deep hole spillway uses the gate hole as the flood discharge method,and the surface overflow tunnel is the weir flow when the radial gate is fully opened.At the same time,the gate hole can also flow out by adjusting the opening of the radial gate.In comparison between the two,the weir flow has the advantages of small working head and large discharge volume,and as the water head rises,the discharge volume increases faster;although the discharge volume of the spillway tunnel is small,the inlet elevation is low,which can discharge the flood earlier.,Improve the utilization rate of the reservoir.When the opening is less than 1.5m,the flow coefficient decreases with the increase of the opening,and when the opening is greater than 1.5m,the flow coefficient increases with the increase of the opening.Because the exit locations of the spillway and spillway tunnels are similar,they are all located on the left bank of the downstream river.The initial plan is a continuous nose sill.After comparison and selection of the plans,the exits of the two holes are uniformly inclined and guided by the side wall.Meet the engineering application,effectively spread the water tongue,and reduce the depth of the riverbed scouring pit.(4)Based on the physical model test,this paper uses the numerical simulation software FLOW-3D to carry out the three-dimensional numerical simulation calculation of the spillway and the spillway.The hydraulic parameters in the spillway and the spillway are in good agreement with the measured values.There are certain errors in the parts with large fluctuations and changes.In general,the numerical simulation calculation results have a certain degree of credibility,which enriches the test results;for the design unit,there may not be sufficient sites for physical model tests,and numerical simulation methods are used.Avoid site occupation,save the cost of physical model construction,and facilitate the design and hydraulic characteristics research and analysis of the engineering discharge structure.