台阶式溢流坝水流跃离的水力特性分析  

Analysis of hydraulic characteristics of flow spring at stepped spillway

作　　者：田嘉宁[1] 赵庆[1] 吴文平[1] 李建中[1] 

机构地区：[1]西安理工大学水利水电学院,陕西西安710048

出　　处：《西北农林科技大学学报（自然科学版）》2008年第3期228-232,共5页Journal of Northwest A&F University(Natural Science Edition)

基　　金：陕西省教育厅基金项目(07JK347);西安理工大学博士科研基金(210602)

摘　　要：【目的】研究台阶式溢流坝泄水过程中产生水流跃离的水力特性。【方法】应用模型试验和量纲分析的方法,分析台阶式溢流坝产生水流跃离的水力特性。【结果】台阶式溢流坝泄水过程中,在跌落水流大部分范围内产生水流跃离现象,其垂直坝面方向的跃离高度为台阶高度的2.6倍,平行坝面方向的跃离长度与台阶高度的比值约为15.6,并在水流回落的水平台阶面上出现压力最大值,其压力水头与台阶高度的比值达到1.88。【结论】当坝坡≥40°,由跌落水流向过渡水流流态转变过程中,在第一级台阶上必然会产生水流跃离,并随坝坡增大水流直接冲击消力池底板。水流跃离的长度、高度随坡度、台阶高度及泄流量的增加而增大;台阶面上的压力大小随水流跃过或冲击而不同。【Objective】 The research is to study the hydraulic characteristics of flow spring caused during the overflow at the stepped spillway.【Method】 The model test and dimensional analysis are adopted to study the hydraulic characteristics of flow spring at the stepped spillway.【Result】 The phenomena of flow spring takes place at a large range of nappe flow during the overflow.The spring height along the vertical direction of dam is 2.6 times height of step.The ratio of height of step to the spring length along the slope direction of dam is 15.6.The maximal value of pressure on the horizontal surface of step where the flow falls appears,and the ratio of pressure head to the height of step is up to 1.88.【Conclusion】 The flow spring will surely happen at the first step during the transfer of nappe flow to transition flow with the slope ≥40°.Meanwhile,the flow spring will directly impact the bottom of still basin with the increase of slope,the length and the height of spring flow will increase along with the dam slope and the height of steps as well as the discharge of overflow raising.Moreover,the pressures on the steps vary with the flow springing or impacting.

关 键 词：台阶式溢流坝 水流跃离 跌落水流 

分 类 号：TV652.13[水利工程—水利水电工程]