平底泄洪洞掺气设施体型研究

掺气减蚀是减免泄水建筑物空化空蚀的常用方法,但对于一些小底坡泄洪洞,如果采用常规的掺气设施结构,掺气空腔往往会被淹没,使其失效反而成为空化源。小底坡泄洪洞的掺气设施体型设计一直是掺气减蚀研究的难题。文章针对平底泄洪洞的掺气减蚀,通过理论分析和1/30的大比尺模型试验,进行了四个方案的对比研究,提出了一种新型的挑坎下游加设贴坡的掺气设施,有效地抑制了空腔回水,获得了稳定的掺气空腔,并且通气量、气水比等掺气特性指标都有明显改善。

Study of the geometries of aerators for flat-bottomed discharge tunnels

Aerators have been widely used to prevent cavitation for discharge tunnels.But to the tunnels with small bot- tom slope,the aerators on them can he drowned out,cease to protect the tunnels,and act potentially as cavitation generators. It is crucial to design this kind of aerators on the tunnels with small bottom slope.Based on the theoretical analyses and 1/30 scale physical model experiments,hydraulic characteristics of air entrainment of the flat-bottomed discharge tunnel for four plans were investigated and a new type of aerator with good aerated effects was developed in the paper.