小石峡水电站导流兼深孔泄洪洞消能工优化试验

Optimization tests on energy dissipator of diversion and deep flood discharge Tunnel of Xiaoshixia Hydropower Station

通过新疆库马拉克河小石峡水电站导流兼深孔泄洪洞原设计方案的消能工试验,发现消力池内发生淹没水跃,水跃旋滚区与闸后射流相叠加,使陡坡段水流剧烈脉动。为了防止护坦段在较大的动水荷载下发生振动和破坏,采用在消力池内设置不同于传统布置方式的悬栅式消能工的方式,即从闸后陡坡末端起布置悬栅,悬栅的安装高度随水跃跃高逐渐抬高,呈台阶式布置。试验表明,台阶式布置悬栅起到了破碎水跃上部剧烈回旋运动的表面旋滚的作用,增大了回流的阻力,从而使水跃向下游移动,由淹没式水跃转化成稍有淹没水跃;在悬栅作用下,陡坡段和消力池内水流脉动明显减弱,浪花溅起高度明显小于加悬栅前的高度,这种悬栅布置方式可为其他同类工程提供参考。

Based on the model tests on the original design scheme for the diversion and deep flood discharge tunnel of Xiaoshixia Hydropower Station on Kumalake River in Xinjiang Uygur Autonomous Region,the submerged hydraulic jump was generated in the stilling pool of the diversion tunnel,and the hydraulic jump superimposed with the jet flows from the floodgate at the steep gradient section,resulting in violent fluctuation of water flows.In order to prevent the apron slab from vibrating and being destroyed by great hydrodynamic load,a suspended grid dissipator was employed,whose installation method was different from that of the traditional one.The suspended grids were installed from the end of the steep slope section and the installation height increased with the length of hydraulic jump,and thus a stair type was formed.The tests show that the suspended grids break up the surface circumflex vortex and increase the backflow resistance,make the hydraulic jump move toward the lower part of the stilling pool,and a little submerged hydraulic jump is thus generated.The fluctuating intensity of water flows at the steep section and in the stilling basin obviously decreases,and splash height is much lower than that before installing suspended grids.The proposed arrangement of suspended grids will be useful for similar projects.