龙落尾起始段掺气设施空腔回水特性研究  

Cavity Characteristics of aerator devices at the beginning of dragon-drop-tail section

作　　者：何佳 吴建华[1] 徐建荣 马飞[1] 彭育 He Jia;Wu Jian-hua;Xu Jian-rong;Ma Fei;Peng Yu(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China;PowerChina Huadong Engineering Corporation Limited,Hangzhou,311122,China)

机构地区：[1]河海大学水利水电学院,南京210098 [2]中国电建集团华东勘测设计研究院有限公司,杭州311122

出　　处：《水动力学研究与进展（A辑）》2021年第5期743-748,共6页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金项目(51179114)。

摘　　要：龙落尾泄洪洞可以大大降低泄洪洞缓坡段的流速,但在龙落尾段其流速仍然较高。在龙落尾起始段设置掺气设施,其佛氏数特性与以往三种类型的掺气设施大不一样,由此,其掺气空腔特性也有不一样的特点。该文在理论分析的基础上,设计了三组12个试验方案,专题研究泄洪洞底坡、掺气坎坎高和挑角等变量在不同来流条件下,掺气坎下空腔回水特性,同时,得到了掺气坎下空腔流态从无回水的净空腔流态到部分回水流态,再到完全回水淹没流态的临界条件。结果表明:随着工作水头的增加,过坎佛氏数表现为先减后增的特性,整个工作条件下,过坎佛氏数较小;另外,在过坎佛氏数增加的区域,虽然工作水头增加,但相对空腔长度减小,净空腔也减小。这是龙落尾起始段掺气设施空腔流态不同于以往三类掺气设施特有的现象。The dragon-drop-tail discharge tunnel can greatly reduce the flow velocity of the gentle slope section,but the velocity still remains very high at the dragon-drop-tail section.Compared with three traditional types of aerator devices,the ones installed at the beginning of the dragon-drop-tail section show different Froude number characteristics,and then their cavity characteristics also differ.Based on theoretical analysis,experimental tests(3 series,12 cases)are conducted to study the characteristics of the cavity filling water at different flow conditions,with the changes in the bottom slopes of the tunnel,the ramp heights,and the ramp angles.The critical conditions of the cavity flow regime conversion are presented from net air cavity to partially filled cavity,and then to fully filled cavity.Results indicate that the Froude number of the flow through those aerators first decreases and then increases with the increase of the working head.Under all working conditions,the Froude number appears comparatively small.Especially,at the operation area with the increasing Froude number,although the working head increased,both the relative cavity length and the net cavity length decrease.This is the unique phenomenon of the cavity flow regime of aerator devices placed at the beginning of the dragon-drop-tail section compared with that of three traditional types of aerated devices.

关 键 词：龙落尾 掺气坎 佛氏数 空腔流态 空腔长度 

分 类 号：TV131[水利工程—水力学及河流动力学]