Research On Flow Characteristics And Discharge Capacity Of Orbital Hydraulic Automatic Control Gate

Some seasonal rivers in the north of China have large age changes,and there are often no floods in years.The installation of gates with lifting devices on this river has the problem of low utilization,therefore,a hydraulic gate that relies on the force of water to realize the automatic opening and closing of the gate has emerged at the historic moment.Orbital hydraulic automatic gate is a new type of hydraulic automatic gate formed by innovation and improvement based on ordinary hydraulic automatic flap gate.Compared with ordinary hydraulic automatic gates,the structure of this new type of hydraulic automatic gates is simpler,and it also solves the problem of sedimentation.However,since this new type of hydraulic automatic gate is still in the preliminary research and development stage,this article conducts a preliminary study on the orbital hydraulic automatic control gate,analyze the flow characteristics of the gate by means of model tests,including flow regime,water depth,downstream velocity field and channel floor time-averaged pressure,and to analyze the gate's discharge capacity by analyzing the relationship between the variables,then analyze the flow coefficient that characterizes the discharge capacity of the gate,and obtain the influencing factors and empirical calculation formulas of the flow coefficient.Finally,the numerical simulation method was used to numerically calculate the flow characteristics of the gate,and compared with the results obtained from the model test to verify the accuracy.The main research results are as flows:(1)Found through model tests of the gate that the water flow condition of the gate is very good,the water surface is calm before the gate,and the water flow is advanced smoothly after the gate;the water depth in front of the sluice is lower than the top edge of the sluice,the outflow state at the sluice hole is free flow,and the water flow after the sluice will not affect the gate's over-current;the velocity gradually decreases with the advancement of water flow,and the distribution pattern of each section varies;the distribution of time-averaged pressure on the channel floor is more complicated.As the flow advances,the cavitation number of the flow increases,and the channel floor has no danger of cavitation.(2)Found out by analyzing the relationship between water level,opening degree and volume flow of different gate types that gate's over-current capacity is closely related to upstream water level,gate opening and gate type.With the increase of the upstream waterlevel and the opening of the gate,the over-current capacity of the track-type hydraulic automatic gate also increases accordingly.The smooth transition of the V2 type gate under various conditions and the smoothness of the water flow are better other than other types of gates.(3)Analysis of the relationship between the variables found that gate inclination angle?,track inclination angle ?,and gate relative opening degree e/H are the main factors affecting the magnitude of the gate flow coefficient,and as the gate inclination angle ?,track inclination angle ?,and gate relative opening degree e/H increase,the flow coefficient will decrease accordingly.Then,the main influencing factors are integrated,and the regression coefficient is used to fit the flow coefficient calculation formula(53)of the orbital hydraulic automatic gate.(4)The numerical simulation software Flow-3D was used to calculate the operating conditions of the gate,and the water flow characteristics of the sluice passing through the gate were analyzed.The obtained results are compared with the measured data,and the results show that the simulated values are basically consistent with the measured values,and the error is within the allowable range.