水电能源科学

旋流竖井在高水头大流量条件下运行时，涡室旋流与引渠来流剧烈碰撞，严重影响水流平稳顺利起旋。对此，通过物理模型试验初步确定了导流坎设计优化原则，并利用数值模拟方法进一步探究不同流量下设置导流坎对旋流竖井流态、压强、流速及空化等水力特性的影响。结果表明，高水头大流量条件下，在上涡室增设导流坎能够有效避免旋流与引渠来流在涡室进口剧烈碰撞，保证水流平稳进入涡室起旋；上涡室进口水深不同流量下降低了48%～54%,引渠与涡室水流衔接平顺；下涡室通气孔掺气速率增加了1.3～1.9倍，竖井段边壁最小水流空化数增大了29%～38%。因此，设置导流坎可提高旋流竖井的泄洪能力，设置导流坎后可适当减小涡室直径以节省工程投资。

When the flow vortex shaft operates at conditions of high water head and large discharge, intense interactions occur between the vortex chamber's vortex flow and the inlet flow from the diversion channel, which severely affects the stability of flow initiation. This study preliminarily established the principles for optimizing the design of flow deflector through physical model experiments, and further explored the influence of setting flow deflector under different flow rates on hydraulic characteristics such as flow pattern, pressure, velocity and cavitation of flow vortex shaft using numerical simulation methods. The results indicate that installing a flow deflector in the upper vortex chamber can effectively prevent intense collisions between the vortex and the diversion channel flow at the chamber entrance, ensuring a smooth inflow into the vortex chamber and stable initiation of the vortex. The water depth at the upper vortex chamber inlet decreases by 48% to 54% at various flow rates, achieving a seamless water flow transition between the diversion channel and vortex chamber. Additionally, the aeration rate of the lower vortex chamber's vent increases by 1.3 to 1.9 times, and the minimum cavitation number along the shaft wall rises by 29% to 38%. Therefore, incorporating a flow deflector enhances the flow vortex shaft's flood discharge capacity and can appropriately reduce vortex chamber diameter for saving engineering investment.