Research On Barrage Effect For Level Rotary Internal Energy Dissipation Discharge Tunnel

In the research foundation of reconstructing leading hole into swirl hole, board hole, blocking hole and other internal energy dissipation ,this paper adopts the method of combining optimization design , experimental study and theoretical analysis together, and discusses barrage effect of level rotary internal energy dissipation discharge tunnel with shaft inlet, and obtains the preliminary achievement of testing and theoretical research.The most heavy flow ability of barrage swirl is controlled by fastenning device and barrage size, the most heavy discharge is more when barrage aperture is bigger, the influence of barrage position on discharge is not obvious; The pressure of the end of the shaft and fastenning device increases which aroused by barrage, and there is a restraining action to flow waving of the shaft; The barrage aperture is smaller, the increase of pressure is heavier, the influence of position to the increase of pressure is not obvious; The positive pressure of the level section in the hole between fastenning device and barrage increases obviously, the change of press along length reduces, mural press in the hydrosphere separating area of outlet of fastenning device becomes positive pressure, which is propitious to the increase of flow cavitate number in the low pressure area of the outlet of fastenning device; The influence of change of swirl cavum diameter caused by barrage to ventilating state is obvious. In the same position, the maximum of ventilating amount is big when barrage aperture is big; When the barrage position tends towards downstream water, the ventilating amount is smaller;The rotary angle of the flow before barrage becomes big, the rotary angle of the flow after barrage comparing with no barrage swirl has less difference, which indicates the swirl flow before barrage whose axial velocity is less than surrounding velocity, and it helps toimprove energy dissipation rate. The effect of energy dissipation is better when barrage aperture is small; the barrage position tends to downstream water ,the effect of energy dissipation is better; When swirl crosses through the barrage, the change of pressure is steady, pulsating pressure reduces; The flow of barrage outlet rotates and spreads, the two phase of hydrosphere discharge with the state of flowing, and link up well with the downstream river , which avoids the unfavorable flow state of discontinuity exporting gasbag in the outlet of the end of the hole.Barrage has a obvious influence on flow state of discharge tunnel and every hydraulic element, the change of every hydraulic characteristic is caused by the change of barrage size and position, and these influence and hydraulic characteristic expression form caused by them is called barrage effect.The study essence of barrage effect in the level rotary internal energy dissipation discharge tunnel is seeking a complex internal energy dissipation, which can reach a good energy dissipation effect, and try not to happen cavitate, and is rational in economic, feasible in technical, and try not to reduce discharge. The study result of barrage effect indicates that barrage rotary complex internal energy dissipation has positive research meaning and project applying prospect.