活动导叶头部圆半径对水泵水轮机飞逸特性的影响研究

以中国某抽水蓄能电站水泵水轮机模型机为研究对象，通过改进活动导叶头部圆半径r，基于Realizable k-ε湍流模型，分析改进活动导叶头部圆半径r对水泵水轮机飞逸特性的影响，充分发挥水泵水轮机在抽水蓄能中的核心作用。结果表明：减小头部圆半径r至(r-0.313) mm，对机组“S”特性存在较佳的改善效果；飞逸工况下无叶区的高速水环逐渐减弱。流体由活动导叶进入转轮叶片流道的过程中，流体的速度由活动导叶出口附近逐渐增大，受高速水环的影响，在无叶区达到最大，随后速度逐渐减小进入转轮，保持在某个较大速度持续流动；飞逸工况下1～5流道转轮叶片进口端旋涡沿着流道逐渐扁平且向转轮叶片后移扩散。转轮叶片进口端旋涡附近压强变化整体呈下降趋势，在叶片进口端出现峰值，转轮叶片进口端旋涡附近压强大小随旋涡位移以及强度而变化；飞逸工况下尾水管的直锥管段分布着大量涡带，且涡带沿着弯肘段逐渐后移到扩散段。回流主要集中在尾水管扩散段边壁附近，在距离转轮中轴线300～500 mm处，回流逐渐减少。

STUDY ON INFLUENCE OF CIRCULAR RADIUS OF GUIDE VANE HEAD ON RUNAWAY CHARACTERISTICS OF PUMP-TURBINE

Based on the Realizable k-ε turbulence model, taking the pump-turbine of a domestic pumped storage power station as the research object, this paper improves the circular radius r of the guide vane head and analyzes the runaway characteristics of the pump-turbine with the improved circular radius of the guide vane head, giving full play to the core role of pump-turbine in pumped storage. The results show that reducing the head circular radius r to （r-0.313） mm has a better effect on the “S” characteristics of the pump-turbine. The high-speed water ring in the vaneless area is weakened obviously under the runaway condition. When the fluid enters the runner blade channel from the guide vane, the velocity of the fluid increases gradually near the outlet of the guide vane and reaches the maximum in the vaneless area due to the influence of the high-speed water ring. Then the velocity decreases gradually and enters the runner and keeps flowing at a high speed. In the runaway condition, the vortex at the inlet of the runner blade of the 1-5 runners is gradually flattened along the runner and spreads back to the runner blades. The pressure change near the vortex at the inlet of the runner blade has a overall downward trend and a peak appears at the inlet of the runner blade. The pressure near the vortex at the inlet of the runner blade varies with the displacement and strength of the vortex. A large number of vortexes are distributed in the straight conical section of the draft tube under the runaway condition, and the vortexes move gradually to the diffusion section along the elbow section. The backflow is mainly concentrated near the side wall of the diffusion section of the draft tube. When 300-500 mm away from the central axis of the runner, the backflow gradually decreases.