Experimental Study On Hydraulic Characteristics Of Curved Gate With Different Bottom Edge Types

With the vigorous development of water conservancy and hydropower in China,the safety of hydraulic structures has been paid much attention.As an important hydraulic structure,the gate is used to adjust the water depth and control the flow according to the actual needs.The radial gate is widely used because of its advantages of small opening force,no gate slot,good flow pattern and easy operation.The bottom edge of the radial gate plays a key role in the discharge of water,and the improper type of the bottom edge affects the normal operation of the gate,and the research on the type of bottom edge of the radial gate is rarely reported.On this basis,three types of radial gate with bottom edge are proposed in this paper,which are back-dip(45°),front and back dip(front 45° and back 30°),and front-dip(45°).The hydraulic characteristics and stability of the radial gate with different bottom edge are analyzed by means of model test,numerical simulation and comparative analysis.The main research results and conclusions are as follows:(1)Based on the physical model test and numerical simulation calculation,the characteristics of the flow state,water level and velocity distribution of the sluice flow under the influence of the back-dip,front-back dip and front-dip bottom edges in different conditions were compared and analyzed.It is concluded that one of the three types has less influence on the reverse excitation effect of wake vortex and gate.Among them,the rake gate has little influence on the water flow when it is discharged under the high head.At the same time,the flow pattern and velocity distribution of the flow through the gate and the distribution law of the time-mean pressure and the fluctuation pressure on the gate under different working conditions are analyzed.(2)Based on the numerical calculation results of the time-mean pressure and fluctuation pressure acting on the radial gate,the results show that the hydraulic characteristics of the front water level discharge at the bottom edge of the back-dip type under the low head are similar to the bottom edge of the front-back type.The influence of the back-dip gate on the fluctuation pressure and the time-mean pressure of the gate panel and bottom edge is great.The front-back dip gate only affects the gate panel.The influence of front-dip gate on the stability of gate panel and bottom edge is less than the other types.(3)By conducting hydraulics tests on the radial gate with different bottom edge types,the problems existing in the operation of the radial gate under the influence of bottom edge were analyzed,and a kind of bottom edge type with better hydraulic characteristics and stability is optimized for the radial gate.The velocity,time-mean pressure and fluctuation pressure of the radial gate under leakage flow are reduced and the stability of the gate is improved.