水跃掺气池的掺气特性

摘要

With a focus on the problems of cavitation damage and the decrease of the energy dissipation rate caused by increasing flow depth and decreasing aeration for traditional stepped spillways under a large discharge rate, a hydraulic jump-aeration stepped spillway was developed, producing aerated flow on the stepped spillways by means of hydraulic jump aeration. Through a physical model test, the air-entrainment characteristics of the hydraulic jump aeration basin were studied, including the effects of the approach flow condition, the length and end sill height of the aeration basin, and hydraulic jump flow regime on air entrainment characteristics. The results demonstrate that the submerged jump shows a better air entrainment effect for the bottom and walls within the aeration basin and the region behind the end sill, and the hydraulic and geometric parameters affect the hydraulic jump flow regime and then affect the air concentration. It is crucial to present a suitable flow regime for air entrainment into the flow on the stepped spillway using the hydraulic jump aeration basin.%针对大单宽流量下传统阶梯溢洪道因流动水深增加，掺气不足，导致极易发生空蚀破坏和消能率降低的问题，提出了一种通过水跃掺气池对阶梯溢洪道流动提供掺气的水跃掺气阶梯溢洪道，采用物理模型试验方法，详细研究了水跃掺气池的掺气特性，包括来流条件、掺气池长度、掺气池尾坎高度、水跃流态对掺气特性的影响。结果表明：在现在的研究范围内，在掺气池内和掺气池尾坎后的区域，无论是底板还是边墙淹没水跃流态都有较好的掺气效果；前述流动参数和结构参数通过影响水跃流态影响掺气效果，在利用水跃掺气池对阶梯溢洪道水流掺气时，流态的控制是重要的。