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二滩水电站是中国在二十世纪建成的最大水电站,电站设有2条龙抬头式泄洪洞,单洞最大泄洪流量为3 800 m~3/s,设计最大流速为45 m/s。1~#泄洪洞在采用常规的掺气设施后,虽然有效地减免了反弧段本身及反弧段下游底板的空蚀破坏,但反弧段下游侧墙仍出现了空蚀破坏。通过大比尺的模型试验,研究了多种掺气减蚀方法,提出了解决高流速、大流量泄洪洞侧墙掺气减蚀方案。2005年,利用研究成果,采用反弧末端上游侧墙突缩(侧墙贴角)加凸型跌坎的三维掺气坎方案,对二滩1~#泄洪洞2~#掺气坎体型进行了改造。随后的水力学原型观测表明,2~#掺气坎区域水流掺气浓度增加,底板和侧墙脉动压力和空化噪声测值平稳,且在合理范围之内。通过连续2个汛期的运行试验和现场检查,改造后的2~#掺气坎体型结构完好,下游未发现明显的空化气蚀现象,成功地解决了侧墙空蚀问题。
Ertan Hydropower Station is the largest hydropower station built in China in the 20th century. The power station has 2 dragon-head-type spillway tunnels. The maximum discharge capacity of a single hole is 3 800 m 3 / s and the designed maximum flow velocity is 45 m / s. 1 ~ # spillway tunnel using conventional aeration facilities, although effectively eliminating the anti-arc itself and the anti-arc downstream of the floor cavitation damage, but the anti-arc section of the downstream wall still cavitation damage. Through large-scale model test, a variety of aeration and erosion reduction methods are studied, and a scheme to solve the aeration and erosion reduction of side wall with high flow velocity and large discharge spillway is proposed. In 2005, based on the research results, a 3-D aerated-ridge scheme with a convex wall on the upstream side wall of the anti-arc end (sidewall) Transformation. Subsequent hydrodynamic prototype observations show that the concentration of water aeration increases in the 2 ~ # aeration tank area, and the fluctuating pressure and cavitation noise of the bottom plate and the side wall are stable and within a reasonable range. Through 2 consecutive flood season operation tests and on-site inspections, the reconstructed 2 ~ # aerated ridges body structure is intact, and no obvious cavitation cavitation phenomenon is found downstream, thus successfully solving the cavitation cavitation problem on the side wall.