Study On Hydraulic Characteristic Of Two-phase Intense Shear Flow In A Rotary-obstruction And Diffuse Compound Inner Dissipation

According to the current problems existing in the dam construction of high head and large discharge,the Vortex Flow Inner Energy Dissipator,which has simple structure,flexible layout,reutilization of diversion tunnel and high rate of energy dissipation and so on,becomes the main direction of water science community.The paper was supported by the Natural Science Foundation of China-Study on hydraulic characteristic of two-phase intense shear flow in a rotary-obstruction and diffuse compound inner dissipation in 2015,and designs the composite inner energy dissipation of level swirling flow for the conditongs of high water head(150m~200m)and large discharge volume(1500rm3/s?2000m3/s).After carrying out the experiment,the hydraulic properties such as the basic flow pattern,the stage-discharge law,the ventilation quantity in air hole,the pressure on the wall,the diameter of the cavity the swirl angle and the velocity were analysed.The research shows the results as follows:1.At different upstream water levels,the flow state of the shaft section can be divided into the open channel flow state,the transition flow state and the submerged flow state.Also,the flow state of the horizontal section can be divided into the open channel flow state,the transition flow state and the stable flow state.At different downstream water levels,the stable flow state can be divided into the far-drive hydraulic jump,the critical hydraulic jump and the submerged hydraulic jump.2.When the downstream water level was less than 1.5D,it had almost no influence on the discharge,and the discharge coefficient ?3 was basically stable at 0.233;When the downstream water level was greater than or equal to 1.5D,the discharge coefficient ?3 was gradually decreased with the rising of the downstream water level.Considered the difference between upsteam and downstream water levels,the discharge coefficient ? was gradually increased with the rising of the downstream water level.3.The different diameter of air hole had little influence on the flow state of spillway tunnel..Under the condition of the air hole diameter being 0.1D,when changing operation mode of the downstream water level from high to low,a "barrier" would be formed in the diversion tunnel at the range from 70m to 110m,which composed by water-air two-phase flow.This "barrier" can significantly consume the energy of discharge flow,and change the flow state from supercritical flow to subcritical flow in diversion tunnel.4.According to the variation law of ventilation quantity and wind velocity of the different air hole diameters,the empirical formula of air hole under the condition of high head and large discharge was proposed,which was:D0 =(0.2?0.3)D.5.The body which connected the shaft well and the level section by the 1/4 ovaland remove the "flip bucket" on the roof,whose radius was less than the horizontal section and shrink the rotary water radius,can effectively eliminate area of low pressure at the export of the spiral flow generator.6.This paper also studied the variation laws of other hydraulic properties of the body:such as the cavity diameter being stable along the way,the water flow angle decreasing along the wya and the variation law of the velocity along radial direction and along the way.which laid a solid foundation for continuing to research on the hydraulic characteristics about the composite inner energy dissipation of horizontal swirling flow.