Model Test Study On Hydraulic Characteristics Of A Water Distribution Project

The water transmission and distribution project is the bridge and link connecting the water source and water users,and has the same important position as the main project(water diversion project).The water distribution hub is the center of water transmission and distribution project,which is the key to ensure water distribution safety,rationality and give full play to project benefits.In order to achieve the optimal matching with the overall design and adapt to the hydraulic conditions under different working conditions,it is necessary for the design unit to carry out hydraulic model test in advance,and to study the hydraulic characteristics of various structures in the water distribution hub.Based on the design of a water distribution project,combined with model test,the rationality of overflow facilities size is verified through the experimental study on the characteristics of overflow facilities,intake gates of South and north trunk lines,and the possibility of boring of water diversion tunnel of water diversion project is reviewed,and the discharge of water diversion tank under different water level conditions,different opening of intake gates of South and north trunk lines,and flow rate of overflow facilities are verified The flow pattern provides the basis for the reasonable operation and safe operation of the water distribution project during the operation period,and provides the hydraulic support for the optimization of the design of the hub buildings.The main research results are as follows:(1)Test results of overflow facilities:the rationality of side weir size and pool top elevation is verified,the flow velocity and pressure of each characteristic section are measured,and the discharge coefficient of weir flow is obtained,which provides data support for design.(2)Test results of north main line characteristics:check the discharge capacity and water surface fluctuation of inlet gate when fully opened,calculate the head loss of intake gate and 1#pressure tunnel through test results,verify flow pattern and minimum submergence depth,measure the pressure of several special sections when the intake gate is fully opened,and recheck whether it meets the design requirements.It is concluded that the discharge capacity of the north main line is determined by the water level difference between the upstream and downstream.It is suggested that the full opening of the intake gate should be adopted in the operation stage.(3)The results of south main line characteristic test:it is found that the water surface of sluice chamber and tunnel behind the gate is stable and the flow pattern is ideal when the inlet gate is fully opened;the flow pattern is complex when the gate is partially opened,and the velocity behind the gate is large;it is concluded that the water level of the water diversion tank determines the flow capacity of the inlet gate when the gate is fully opened.It is suggested that in order to improve the flow pattern behind the gate,the low water level operation should be adopted when the gate is partially opened.(4)It is found that the minimum submergence depth of intake sluice and the minimum pressure of tunnel body jointly determine the minimum safe operation water level in the basin.According to the test analysis,it is suggested that the lowest operating water level is 512.0m.The results of model test show that the general layout of the water distribution tank is basically reasonable,and the design scheme can meet the requirements of water distribution.The research results of this paper also provide reference for similar engineering design.