大单宽流量低傅汝德数收缩墩底流消力池的试验研究  

Experimental study on underflow stilling pool with contraction pier of large unit width discharge and low Froude number

作　　者：李一川 牛争鸣[2] 李奇龙[2] 王立杰[2] LI Yichuan;NIU Zhengming;LI Qilong;WANG Lijie(Hunan Provincial Key Laboratory of Hydropower Development Key Technology, Changsha 410014,Hunan, China;Xi an University of Technology, Xi an 710048, Shaanxi, China)

机构地区：[1]水能资源利用关键技术湖南省重点实验室,湖南长沙410014 [2]西安理工大学水利水电学院,陕西西安710048

出　　处：《水利水电技术》2018年第5期77-83,共7页Water Resources and Hydropower Engineering

基　　金：水能资源利用关键技术湖南省重点实验室开放基金资助项目(PKLHD201301)

摘　　要：为解决大单宽流量、低傅汝德数底流消能中存在振荡水跃,进而导致消力池内流态不稳定、水面波动大、消能率低等问题,采用模型试验的方法,对在消力池前设置收缩墩后的收缩扩散与底流复合消力池进行了研究。结果表明:设置Y型收缩墩后消力池内呈较为稳定的收缩射流与淹没水跃的三元复合流态,水流更为稳定,振荡水跃消失,可有效解决池内的水流间歇性振荡和水面大幅波动等问题。同时,设置收缩墩后,可有效降低池内最大临底流速,由近30 m/s降至约20 m/s。消能率由60.93%提升至66.61%,消能效果显著。此外,下游河道冲刷大大减小。最不利冲刷工况下的2年一遇洪水时,基岩最大冲深由近32.0 m降为5.6 m。消力池前设置收缩墩,对于因受地形地质等客观条件限制,无法通过改变池长池深来解决大单宽低傅汝德数的底流消能问题,提供了一种新思路。In order to solve the problem of that oscillating hydraulic jump is there in the underflow energy dissipation of large unit width discharge and low Froude number,and then causes an unstable flow regime with large fluctuation of water surface and lower energy dissipation rate,etc. in stilling pool,the method of model experiment is adopted to study the shrinkage diffusion and underflow composite stilling pool after arranging contraction pier in front of it. The result shows that a ternary composite flow regime of shrinkage diffusion and submerged hydraulic jump presents in the stilling pool after arranging the Y-typed contraction pier,of which the flow is more stable without oscillating hydraulic jump,thus the problems of the intermittent oscillation of water flow and large amplitude fluctuation of water surface,etc. can be effectively solved. At the same time,the maximum near-bottom flow velocity can be effectively decreased from nearly 30 m/s to about 20 m/s,while the energy dissipation rate is increased from 60. 93% to 66. 61% with a significant energy dissipation effect. Moreover,the river channel erosion is largely decreased. Under the most unfavorable erosion condition of the flood with the recurrence interval of 2 years,the maximum erosion depth of the bed rock is decreased from 32. 0 m to 5. 6 m. The arranging contraction pier in front of stilling pool provides a new idea for solving the problem of underflow energy dissipation of large unit width discharge and low Froude number,which cannot be solved through changing the length and depth of stilling pool due to the limitation from the objective conditions of the geology,topography,etc.

关 键 词：单宽流量 傅汝德数 Y型收缩墩 振荡水跃 收缩扩散与底流复合消力池 

分 类 号：TV131.61[水利工程—水力学及河流动力学]