龙英水库溢流坝导墙收缩角对泄流水力特性影响试验研究  

Experimental study of influence of overflow dam guide wall contraction angle on discharge hydraulic characteristics for Longying Reservoir Project

作　　者：肖天培 张小飞[1] 黄佳敏 覃培 XIAO Tian-pei;ZHANG Xiao-fei;HUANG Jia-min;QIN Pei(College of Civil Engineering and Architecture,Guangxi University,Nanning 530000,China)

机构地区：[1]广西大学土木建筑工程学院,南宁530000

出　　处：《广西水利水电》2021年第2期1-5,共5页Guangxi Water Resources & Hydropower Engineering

摘　　要：通过水工模型试验,观测不同收缩角时,导墙产生的冲击波对大坝泄流水力特性以及挑流消能的影响。结果表明:龙英水库由于溢流坝下游堰面水流流速大,相应的弗劳德数(Fr)大,导墙收缩产生的冲击波的传播速度远小于水流流速,冲击波波角小,冲击波只沿导墙边向下游传播,对非紧邻导墙的水流流态影响不大;当龙英水库大坝导墙收缩角不大于10°,由导墙收缩产生的并沿导墙边流动的左右两股相对较强的水流,在溢流面、挑坎处水流没有出现交叉碰撞,挑流水舌稳定,当导墙收缩角不小于15°时,左右两股水流在挑坎处或挑坎下游出现交叉碰撞,收缩角越大交叉碰撞的位置越靠近上游,挑流水舌越不稳定,当导墙收缩角大于20°时,需要采用工程措施改善挑坎处水流流态,减小雾化和下游的冲刷;挑流挑距主要是受挑坎的几何形状和尺寸、坎上水流流速影响,导墙收缩角影响不大。Hydraulic model test was conducted for Longying Reservoir Project to observe the influence of shock wave caused by guide wall on dam discharge hydraulic characteristics and energy dissipation at different contraction angles.The results of test demonstrate the propagation velocity of the shock wave caused by the contraction of guide wall was much smaller than the flow velocity due to the high flow-rate on the weir surface downstream of the overflow dam and the corresponding high Froude number Fr;the shock wave angle was small,and the shock wave only propagated downstream along the edge of the guide wall,which renders little effects on the flow pattern not adjacent to the guide wall.When the contraction angle of guide wall is not greater than 10°,two relatively strong streams resulted from guide wall contraction flow along the left and right edges of guide wall,there was no cross collision at the overflow surface and the flip bucket,and the water jet was stable.When the contraction angle is not less than 15°,cross collision of two streams occurred at the flip bucket or downstream of the flip bucket;the larger the contraction angle was,the closer the collision position was to the upstream and the more unstable the water jet was.When the contraction angle was greater than 20°,it was necessary to adopt engineering measures to improve the flow pattern at the flip bucket and reduce atomization and downstream scour.The trajectory distance was mainly affected by the geometric shape and size of the flip bucket as well as the flow velocity on the flip bucket,and the contraction angle of the guide wall had little effect.

关 键 词：溢流坝 导墙 收缩角 水力特性 水工模型试验 龙英水库 

分 类 号：TV131.61[水利工程—水力学及河流动力学]