消能墩在分段加墩式台阶消能工中的应用研究

Application of Energy Dissipation Piers in Segmented Pier Type Step Energy Dissipator

为了提高台阶消能工的掺气浓度,减缓空化空蚀危害,提高消能率,提出了分段加墩式台阶消能工,采用数值模拟的方法,研究消能墩正墩和反墩布置形式对分段式加墩台阶消能工水力特性的影响。结果表明,分段加墩式台阶消能工在台阶平直段消能墩附近产生水跃,正墩布置形式水跃掺气效果较好,沿程掺气浓度较高,减缓空蚀效果较好;各台阶段沿程流速逐渐增大,正墩布置具有更低的流速,消能效果更好;消能墩迎水面和上游区域形成了较大范围的正压,消能墩顶部及背水面产生了负压,正墩布置对水流的阻碍作用较高,反墩布置负压较大;各流量工况下,两种布置形式消能率较高,正墩布置形式在流量较大时消能率更高,具有更好的消能效果。正墩布置形式在减小台阶空蚀破坏和提高消能率方面效果更好,可为分段加墩式台阶消能工结构设计提供一定的参考依据。

In order to improve the aerated concentration of the stepped energy dissipator,mitigate the damage of cavi-tation and cavitation erosion,and improve the energy dissipation rate,the stepped energy dissipator with segmented piers was proposed.The influence of the arrangement of the front pier and the reverse pier of the energy dissipator on the hy-draulic characteristics of the stepped energy dissipator with segmented piers was studied by numerical simulation.The re-sults show that the stepped energy dissipators with segmented piers generate hydraulic jump near the energy dissipators in the flat and straight section of the terrace.The arrangement of the main pier has better effect of hydraulic jump aeration,higher concentration of aeration along the way,and better effect of cavitation erosion mitigation;The flow velocity along each stage increases gradually,and the arrangement of the main pier has lower flow velocity and better energy dissipation effect;A large range of positive pressure is formed on the upstream area and the upstream area of the energy dissipation pier,and negative pressure is generated on the top and back surface of the energy dissipation pier.The arrangement of the positive pier has a high blocking effect on the water flow,and the arrangement of the reverse pier has a large negative pressure;Under each flow condition,the energy dissipation rate of the two arrangement forms is higher,and the energy dissipation rate of the positive pier arrangement form is higher when the flow is larger,which has better energy dissipa-tion effect.The arrangement of the main pier has better effect in reducing the cavitation damage of the step and improving the energy dissipation rate,which can provide a reference for the structural design of the stepped energy dissipator with segmented piers.