Study On Hydraulic Characteristics Of Floating Hydraulic Automatic Control Gate

Floating hydraulic automatic control gate is controlled by the upstream water level,and can be opened and closed automatically by using its own gravity and upstream water pressure.Its operation is simple and reliable.Through theoretical analysis,model experiment,regression analysis and numerical simulation,the hydraulic characteristics of floating hydraulic automatic control gate are studied in this paper.Firstly,the working principle and stress condition of floating hydraulic automatic control gate are analyzed,and then the model experiment is carried out.According to the experimental results,the hydraulic characteristics of floating hydraulic automatic control gate,including water depth,are analyzed.Research on flow velocity and average hydrodynamic pressure,comparative analysis of flow capacity of different types of floating hydraulic automatic control gates,correction of flow calculation formula of floating hydraulic automatic control gates,analysis of main factors affecting flow coefficient of floating hydraulic automatic control gates,and obtained flow coefficient calculation formula of floating hydraulic automatic control gates.Fluent numerical simulation analysis is carried out,and the numerical simulation results are compared with the model experimental results.The research results can provide data basis and calculation basis for the practical application of floating hydraulic automatic control gate.The main research results are as follows:(1)The weight and gravity center of the floating hydraulic automatic control gate are the control factors of its opening and closing.After stable operation,the gate is always in a balanced state and maintains a certain upstream water level.The gate has a good gradual,flexible and stable operation.The experimental study shows that when the front inclination angle of the gate is greater than 75,and the back inclination angle is greater than 65,the center of gravity of the gate changes too much to open normally.(2)Under the condition of free outflow of gate hole,the flow state of floating hydraulic automatic control gate is stable,and the water depth behind the gate has no effect on the gate overflow;the velocity distribution of channel behind the gate is uniform and the change is gentle;the change of the average dynamic water pressure on the bottom of the channel is complex and has obvious sudden drop,and the change of the average dynamic water pressure on the whole is wavy.The change of the average dynamic water pressure is due to the change of the water level of the channel of floating hydraulic automatic control gate.The change of hydrostatic pressure is caused by the change of flow velocity.(3)The flow capacity of the floating hydraulic automatic control gate is analyzed.It is proved by comparison that the flow capacity of the floating hydraulic automatic control gate of type s2a3(forward inclination angle ? equals 70,backward inclination angle ? equals 65)is stronger.The flow calculation formula of the floating hydraulic automatic control gate is revised.(4)It is proved that the main factors affecting the discharge coefficient of the floating hydraulic automatic control gate are the forward inclination angle ?,the backward inclination angle ? and the relative opening e/H of the gate.The formula for calculating the discharge coefficient of the floating hydraulic automatic control gate is obtained by means of regression analysis.(5)In the numerical simulation results,the flow state of the floating hydraulic automatic control gate is stable,the velocity distribution is uniform,and the variation regularity of the time average hydrodynamic pressure is strong,and the numerical simulation results are basically consistent with the water depth,velocity and time average hydrodynamic pressure in the model test results.