锦屏一级水电站泄洪洞的掺气减蚀及消能防冲问题

锦屏一级水电站泄洪洞具有“大泄量、特高水头、超高流速”的特点，高速水流空化空蚀问题非常突出。为了解决其掺气减蚀、泄洪消能防冲及出口挑流河道归槽的问题，锦屏一级水电站在泄洪洞的龙落尾、掺气坎、补气洞及出口挑坎等关键部位采用了特定的工程技术。对这些特定工程技术的模型实验结果、原型观测资料及设计规范进行了分析，并结合乌江渡水电站、二滩水电站等工程评价了规范的适用性。分析结果表明锦屏一级泄洪洞的洞顶余幅、龙落尾体型、出口燕尾坎消能工等设计合理，掺气设施的掺气保护满足要求，补气及通气系统效果良好，没有发生空化空蚀现象。同时，在掺气空腔长度、风速、补气量、泄洪雾化等方面的模型缩尺效应明显，需要后续工程在设计阶段予以重视并进行更为深入而细致的研究。

Problems from energy dissipation for erosion-control and aeration for cavitation alleviation of spillway tunnel of Jinping I Hydropower Station

The spillway tunnel of Jinping I Hydropower Station has characteristics of large discharge，super high water head and ultra-high flow rate，and then the problem of cavitation and cavitation erosion from high-velocity flow is quite prominent. In order to solve the problems from the aeration for cavitation alleviation and the energy dissipation for erosion-control during flood discharge as well as keeping the jet flow from the outlet returning into the main river channel，several specific engineering technologies are adopted for the key locations，i. e. dragon-drop-tail section，aerator，vent shaft，outlet flip-bucket，etc. ，of the spillway tunnel of the hydropower station. The model experiment results，prototype observation data and design specifications of these technologies are analyzed herein，and then the applicabilities of the specifications are evaluated in combination with those for the projects of Wujiangdu Hyropower Station，Ertan Hydropower Station，etc. the analysis result shows that the designs of the remaining height of tunnel，the shape of dragon-drop-tail section and the swallow-tailed energy dissipator are reasonable，while the aeration protection from the aeration facility can meet the relevant requirement and the effect of venting and ventilation system is better，thus no any phenomena of cavitation and cavitation erosion occur. Meanwhile，the scale effects o the models are ignificant in the aspects of the length，wind speed，venting amount，flood discharge atomization，etc. of the aeration cavity， which are necessary to be deeply and detailly studied with relevant attentions in the design stage of the project for the successive construction.