Author(s): Qin Yue; Wang Zhigang; Li Ling; Chen Yongcan; Liu Zhaowei
Linked Author(s): Yongcan Chen, Zhaowei Liu
Keywords: Erator slight slope flow resistance slope cavity backwater low Froude number
Abstract: Aerators are critical devices in preventing cavitation damage in high-velocity spillway structures. However, under conditions of low Froude numbers and slight slopes, cavity backwater is prone to obstruct aeration holes, affecting the aeration effectiveness. Therefore, the introduction of a flow resistance slope downstream of the aerator is being considered as a measure to effectively mitigate the adverse effects of backwater. Through theoretical analysis and 1:25 scale model experiments, a mathematical model for predicting the area of water accumulation associated with varying flow resistance slopes was developed, and the impact of local flow resistance slopes on cavity water accumulation in slight slope spillways was investigated. The research indicates that the flow resistance slope affects water accumulation in cavities by influencing the jet impact angle. For slight slope spillways, considering the impact of changes in the angle of the flow-resistance slope on the water accumulation area, the cavity states can be categorized into three phases: the overflow phase, water-blocking optimization phase and clean cavity phase. In the experimental conditions, taking into account both the blocking and aeration effects, the optimal angle appears in the water-blocking optimization phase (21% <γr<41%), where a stable cavity forms under the jet, and the contact between water and air is sufficiently enhanced. This study can provide a technical reference for optimizing the design of aerators in slight slope spillways under low Froude number flow conditions.
Year: 2025