高水头弧形闸门突扩跌坎及掺气设施体型研究与工程实践

Study of shape design of the aerator with sudden lateral enlargement and bottom drop behind high-head radial gate and its engineering applicaton

随着水电工程的泄水孔道设计向高水头方向发展,采用突扩跌坎弧形门布置方式可以较好的解决高水头弧形闸门的止水安全等问题;但结合掺气减蚀设施布置的突扩跌坎具有不同于一般闸门孔口的水力特性,一些工程出现了原因各异的破坏现象。通过对国内外部分采用突扩跌坎布置的泄水孔道体型参数以及运用情况的分析,对水布垭面板堆石坝高水头放空洞突扩跌坎及掺气设施进行了综合选型,并进行了水力学模型试验,研究了突扩跌坎闸门区的水力特性、空化特性及水流掺气特性,分析了530m长的高速明流洞只设一道掺气设施的可行性。经过原型工程长时间、超高水头的泄洪考验,放空洞突扩跌坎闸门区与高速明流洞均无空蚀现象,表明水布垭面板堆石坝高水头放空洞弧形闸门突扩跌坎掺气设施选型以及在530m长的高速明流洞只布置一道掺气设施研究取得了成功,可供同类高水头泄水建筑物设计时参考。

With application of increasingly more high-head discharge channels, aerator with sudden lateral enlargement and bottom drop becomes an effective device to ensure water sealing safety of high-head radial gate. Its hydraulic characteristics are quite different from a regular gate orifice, however, and structural damages occurred from different causes in several projects. By analyzing the shape parameters of such device and its application in several water release channels in China and overseas, a comprehensive shape selection and hydraulic model test were applied to the high-head emptying culvert of the Shuibuya hydropower station. This work focused on the studies of hydraulic, cavitation and aeration behaviors of the flow around the radial gate and the feasibility of installing only one aerator in a high-speed free-surface flow tunnel of 530m long. Also long-time prototype observation was conducted to check the gate region and the high speed-free flow tunnel under super high-head flood discharge. In this observation, no cavitation erosion has been found. This shows a success of Shuibuya in its aerator shape and its one-aerator scheme, and it would provide design reference for similar high-head discharge structures.