摘要
依据文献分析了有限宽度水槽突然扩散、固定扩散角渐变扩散、无边界平板扩散和急流扩散4种典型明渠扩散段水流的共同流动特征.给出了有限宽度水槽突然扩散段水流宽度的沿程发展规律,以及在平底明渠急流扩散段设计时,为防止水流脱离的扩散角计算方法和突然扩展区急流扩散的边界方程;通过不同底坡比降的试验和原型资料分析,论述了陡坡扩散区水深沿程变化特点、沿程各断面横向分布规律,介绍了陡坡上水平扩散角的计算方法与扩散角最大值的存在.通过大扩散角水槽试验,发现在扩散段不同流态的过渡水流现象及稳定性不一样.上游来流为急流时,下游水跃进入扩散段就是水流失稳、主流偏转的开始;采用潜没式三角翼可以防止扩散段回流发生,提高过流均衡性.
The same supercritical flow characteristics of four kinds of diffused section of open channel were analyzed,such as abrupt diffusion section of flume with limited width,transition section with fixed angle,diffusion section of the flat with no border and supercritical flow diffusion section of steep slope. The developing law of the flow width along the stream was given in the abrupt diffusion section of flume with limited width. The calculation method of the spread angle was introduced for preventing flow separation when designing in the supercritical flow diffusion section of open channel with plane bottom,and the boundary equation of supercritical flow diffusion was given in the abrupt diffusion flume. By experiments in different bottom slope gradient and analysis of prototype observation data,the transverse distribution law of cross sections and changing characteristics of depth of water along the steep slope diffusion section were discussed. The calculation method of horizontal spread angle on steep slopes were introduced,as well as the maximum value of spread angle. Through the experiment of the flume with large spread angle,it is found that transitional flow phenomenon and stability of different flowing form are different in diffusion section. When the incoming flow is supercritical flow,the flow begins to become instable and deflecting once the hydraulic jump occurs in the diffusion section. The submerged triangle wing can restrain the occurrence of circle flow and improve the flow balance.
引文
[1]宁利中.急流扩散段冲击波的水力计算问题[J].西北水利发电,2004,20(3):1-4.
[2]娄妍.急流冲击波特性分析及计算方法设计[D].南京:河海大学,2006.
[3]张志昌,李若冰,傅铭焕,等.矩形明渠自由水跃长度的理论分析[J].水力发电学报,2014,32(6):108-114.
[4]刘文华,刘焕芳,金瑾,等.泄槽菱形冲击波水力特性的试验研究[J].中国农村水利水电,2010(11):111-118.
[5]樊有锋,刘韩生,姬春利.对称直线收缩段急流冲击波的水力计算[J].中国农村水利水电,2009(10):121-124.
[6]华绍曾,杨学宁.实用流体阻力手册[M].北京:国防工业出版社,1985.
[7]天津大学水力学教研室.水力学[M].北京:人民教育出版社,1980.
[8][德]考夫曼W.工程流体力学[M].上海:上海科学技术出版社,1959.
[9]特里顿D J.物理流体力学[M].北京:科学出版社,1986.
[10]王治祥.陡槽水力扩散特性[J].西北水资源与水工程,1990,1(4):48-52.
[11]宋慧芳.恒定有压扩散流局部非稳态流动研究[D].天津:天津大学,2007.
[12]朱济圣.闸下急流扩散的水力理论和工程实践[J].水动力学研究与进展,1989,4(4):115-121.
[13]中国科学院水工研究室.高速水流论文译丛(第一辑第二册)[M].北京:科学出版社,1958.
[14]赵振兴,何宁.孔板泄洪洞水流三维数值模拟研究[J].华北水利水电学院学报,2010,31(1):10-13.
[15]谢波,金峰,王才欢.边墙设计中水流冲击波水力特性问题的探讨[J].长江科学院院报,2006,23(2):61-64.
[16]赵振国.急流在平板上的扩散[J].水动力学研究与进展,1984(2):89-97.
[17]李崇智.陡坡明渠水流扩散[J].水利学报,1984(2):45-49.
[18]孙东坡,曹帅,宋永军,等.改善泄洪放空洞挑流消能效果的试验研究[J].华北水利水电学院学报,2013,34(6):8-11.
[19]周森.西霞院工程王庄引水闸水力学关键问题及模型试验研究[J].中国农村水利水电,2012(10):105-107.
[20]齐昕,刘嘉夫,王立杰.抽水蓄能电站侧式进出水口残留围堰对水流扩散影响研究[J].轻工科技,2014(2):54-55.
[21]滕凯,张丽伟.弧度梯形渠道收缩水深计算方法的简化[J].华北水利水电学院学报,2013,34(3):55-58.
[22]杨玉海,李嫣.浅议正槽溢洪道泄槽设计[J].中国水运,2011,11(3):128-130.
[23]余东,林建国,陆杰.沿岸回流区污染物对流扩散的数值模拟[J].大连海事大学学报,2007,33(3):74-77.