三峡地下电站进水口漩涡特性试验研究

Study on intake vortex characteristics of the Three Gorges underground hydropower station

泥沙模型试验表明三峡地下电站进水口出现立轴漩涡,影响机组安全平稳运行。为此,依托三峡水利枢纽1∶100水工整体和地下电站1∶70水工半整体模型,针对枢纽运行期不同淤积边界条件,开展了地下电站进水口前漩涡特性试验研究。成果显示,地下电站引水条件复杂,形成正向和侧向混合进流。但各机组进口前均未出现危害机组安全稳定运行的吸气漩涡,仅在其左、右侧1#和6#机进口偶尔出现浅层不吸气漩涡。从枢纽调度运行安全的角度,目前连通道可暂不封堵,需加强观测及相关研究,必要时实施封堵。

A series of tests were carried out to study the power intake vortex on a lumped hydraulic model of scale 1∶ 100 for the Three Gorges project and a semi-lumped hydraulic model of scale 1∶ 70 for the underground hydropower station. Results revealed that the flow condition in the power intakes is very complex with a mixed patterns inflow coming from the front and sidewise. The intensity of the vortices is generally quite low, however,and inspiration vortex that do harm to the safe or the steady operation of the power plant were not observed on these models,although air-entraining vortices occasionally appeared in the intakes of unit 1 and unit 6. Due to guide vane effect,the trash-rack framework made of boards,girders and frustas could play a crucial role in preventing inspiration vortices.