环境气压对掺气设施空腔长度的影响分析

低气压环境下泄水建筑物空化空蚀风险增大,环境气压对掺气减蚀效果的影响程度是高海拔地区高坝水力设计时需重点关注的问题。采用CFD数值仿真方法,建立跌坎和挑坎两种不同体型的掺气设施模型,分析不同环境气压下的掺气设施的空腔长度,研究环境气压对高速水流掺气效果的影响。结果表明,环境气压越低,高速水流掺气空腔长度越小,掺气效果越弱,高海拔地区高速水流防蚀设计应合理考虑环境气压的影响程度。

Analysis of Ambient Air Pressure Effect on Cavity Length of Aeration Facility

Discharging structures have a high risk of cavitation in low air pressure environment. The impact of ambient air pressure on the aeration cavitation reduction is a scientific concern in high-dam hydrodynamic design in high altitude areas. The CFD numerical simulation method is employed to establish different aeration facility models for step-down floor and flip bucket, respectively. The cavity length of aeration facilities are analyzed under different ambient air pressures, and the impact of ambient air pressure on aeration of high-speed water flow is studied. It shows that lower ambient air pressure results in shorter cavity length of high-speed water flow and weaker aeration effect. The ambient air pressure effect should be reasonably considered in the cavitation prevention design for high-speed water flow in high altitude areas.