消力池底板磨蚀破坏的水力学试验研究

Hydraulic Experimental Study on Abrasion Damage of Stilling Basin Floor

高水头电站泄洪消能难度较大,消能设施容易发生破坏。笔者采用模型试验和理论分析相结合的方法对铜街子水电站的泄洪消能问题进行研究。表孔闸门对称开启时,消力池的消能效果较好,从流场和压力分布特性可排除体型设计的影响;表孔闸门非对称开启时,消力池内形成流速较大的横向回流,回流形态与底板环形破坏带相似,可以判断回流携沙长期磨损是消力池底板破坏的主要原因,运行时应尽量避免非对称的开启方式。笔者通过比较表孔闸门对称和非对称两种开启方式,分析消力池流态、流场及压力特性,判断得出了消力池底板的破坏原因,并优化了电站的运行方式。研究成果对消力池的修复工作和电站后期的安全运行具有较大的指导作用。

It is difficult to discharge and dissipate energy in high head hydropower station,and the energy dissipation facilities are easy to be damaged.In this paper,the model test and theoretical analysis are combined to study the flood discharge and energy dissipation at Tongjiezi Hydropower Station.The results show that the energy dissipation effect of stilling basin is better when the surface sluice gate is opened symmetrically,and the influence of shape design can be excluded from the characteristics of flow field and pressure distribution;when the surface sluice gate is opened asymmetrically,the transverse backflow with larger velocity is formed in the stilling basin,and the shape of the backflow is similar to the annular failure zone of the stilling basin floor,which can be concluded that the long-term abrasion of backflow sediment carrying is the main reason for the floor damage of stilling basin,and the asymmetric opening mode should be avoided as far as possible during the operation.By comparing the symmetric and asymmetric opening modes of the surface sluice gate,the flow pattern,flow field and pressure characteristics of the stilling basin are analyzed,and the damage reason of the stilling basin floor is determined,and the operation mode of the hydropower station is optimized.The study results have played a great guiding role for the repair of stilling basin and the safe operation of the hydropower station in the later stage.