摘要
【目的】窄河谷高拱坝常采用表孔宽尾收缩射流技术以实现高拱坝表深孔无碰撞泄洪消能。宽尾墩收缩比过大时,水舌纵向拉伸不充分,会导致入水集中加剧下游冲刷;收缩比过小时,流道内发生壅水,可能降低表孔泄流能力同时会恶化挑流水舌流态。找到壅水发生的收缩比临界值可为宽尾墩体型设计提供依据。【方法】采用水工模型试验和三维数值模拟计算相结合的方法,研究了宽尾墩收缩比、始折点、收缩段长、堰面俯角和堰顶水头对流态的影响。【结果】结果表明:在其他参数相同仅改变收缩比的条件下,随着宽尾墩收缩比的缩小,存在一个临界收缩比,当收缩比小于临界收缩比时,表孔内出现壅水流态;基于360多种计算体型工况试验,得到了48组临界收缩比试验数据。【结论】给出了临界收缩比与堰顶水头、堰面曲线定型设计水头、堰顶与闸墩始折点高差、收缩段长和堰面俯角的定量关系式,经验证该公式具有较高精度,可为高拱坝表孔宽尾墩体型设计提供参考。
[Objective]The flaring gate pier contraction jet technology is commonly employed in narrow valley high arch dams to facilitate collision-free flood discharge and energy dissipation of the surface spillway and deep hole.Excessive contraction ratio of the flaring gate pier result in inadequate longitudinal tension of the jet flow,causing water inflow concentration and exacerbating downstream scouring.Conversely,if the contraction ratio is too small,backwater can develop in the flow channel,leading to a potential reduction in the discharge capacity of the surface spillway and degradation of the jet shape.Determining the critical value of the contraction ratio for backwater can serve as a foundation for designing the shape of the flaring gate pier.[Methods]The effects of contraction ratio,initial turning point,contraction section length,weir surface pitch angle,and head on weir crest on the flow state of a flaring gate pier are investigated through hydraulic model experiments and three-dimensional numerical simulations.[Results]The results indicate that,with all other parameters held constant and only the contraction ratio varied,a critical contraction ratio exists for the flaring gate pier.When the contraction ratio falls below this critical value,backwater flow occurs in the surface spillway.Through over 360 calculation cases,48 sets of experimental data on the critical contraction ratio are collected.[Conclusion]The results provide a quantitative relationship between the critical contraction ratio and the head on weir crest,stereotyped design head,height difference between the crest and initial turning point,length of the contraction section,and angle of the weir surface.The formula’s high accuracy has been verified,providing valuable reference for designing the flaring gate pier of a high arch dam.The formula’s high accuracy has been proven,providing valuable reference for designing the flaring gate pier in the surface spillway of a high arch dam.
作者
马玉晨
张法星
喻泽
郭帆
孙宇佳
MA Yuchen;ZHANG Faxing;YU Ze;GUO Fan;SUN Yujia(State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,Sichuan,China)
出处
《水利水电技术(中英文)》
北大核心
2025年第1期169-180,共12页
Water Resources and Hydropower Engineering
基金
国家自然科学基金项目(52192673)。
关键词
表孔
宽尾墩
模型试验
数值模拟
堰顶水头
收缩比
surface orifice
flaring gate piers
model test
numerical simulation
head on weir crest
contraction ratio
