非对称窄缝挑坎水力特性研究
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摘要
非对称窄缝挑坎是针对山区弯曲河道泄洪消能的一种新型消能工。基于水力学模型试验研究了偏转角为0°~10°非对称窄缝的水力学特性,重点分析了挑流段水面线特性、边墙压力分布、挑距及入水范围。模型试验上游来流采用有压装置生成,参照规范建议值选定了窄缝消能工模型的收缩比、挑角等参数。试验结果表明:弗劳德数Fr与非对称偏转角对挑流水面线、边墙荷载、挑距有较大影响。非对称窄缝挑坎可以有效地使挑流发生转向,相比对称窄缝挑坎,在相近的流量下非对称窄缝水舌扩散更为均匀,从而有效减弱了水舌对两岸的冲刷,减小了水舌对河床的冲击力度。
Asymmetric slit-type flip bucket is a new type of energy dissipater for energy dissipation of flood discharge in mountainous curved rivers. In this study,laboratory experiments were conducted to study the hydraulic performance of an asymmetric slit-type flip bucket,including the effects of deflection angles on the surface profile,wall pressure,and the jet distance. A pressurized device was employed to generate the upstream supercritical flows,and the design parameters of the flip bucket,such as the shrinkage ratio and the flip angle,were selected based on recommendations of hydraulic engineering guidelines. The experimental results show that Froude Number( Fr) and the asymmetric deflection angle are the key factors that influence the jet trajectory,sidewall loading,and the jet distance. Compared with the symmetrical ones,the asymmetric slit-type flip buckets force greater vertical and longitudinal spread of the jet,reducing the impact of jet tongue on the river bed.
Asymmetric slit-type flip bucket is a new type of energy dissipater for energy dissipation of flood discharge in mountainous curved rivers. In this study,laboratory experiments were conducted to study the hydraulic performance of an asymmetric slit-type flip bucket,including the effects of deflection angles on the surface profile,wall pressure,and the jet distance. A pressurized device was employed to generate the upstream supercritical flows,and the design parameters of the flip bucket,such as the shrinkage ratio and the flip angle,were selected based on recommendations of hydraulic engineering guidelines. The experimental results show that Froude Number( Fr) and the asymmetric deflection angle are the key factors that influence the jet trajectory,sidewall loading,and the jet distance. Compared with the symmetrical ones,the asymmetric slit-type flip buckets force greater vertical and longitudinal spread of the jet,reducing the impact of jet tongue on the river bed.
引文
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[13]MINOR H E,HELLER V,HAGER W H,et al.Ski Jump Hydraulics[J].Journal of Hydraulic Engineering,2005,131(5):347-355.
[2]赵欣.窄缝挑坎的最新研究动态[J].水利科技与经济,2010,16(3):309.
[3]贝丽克孜·亚森.平行边墙出口窄缝挑坎消能特性研究[J].水利科技与经济,2016,22(8):1.
[4]吴文平,韩瑜,张晓宏.窄缝挑坎底板压力分布的数值分析[J].西安理工大学学报,1997,16(1):73.
[5]DENG Jun,YANG Zhengli,TIAN Zhong,et al.A New Type of Leak-Floor Flip Bucket[J].Science China(Technological Sciences),2016,59(4):566.
[6]李桂芬,高季章.窄缝式消能工在泄水建筑物中应用条件的初步研究[J].水利水电技术,1984,2(10):9.
[7]刘韩生,倪汉根,梁川.非对称窄缝挑坎的边墙曲线计算方法[J].水力发电学报,2001(3):60.
[8]倪汉根,刘韩生,梁川.兼使水流转向的非对称窄缝挑坎[J].水利学报,2001,32(8):85.
[9]倪汉根,刘韩生.窄缝式消能工收缩段的体型设计[J].水利学报,1999,30(2):85.
[10]戴振霖,宁利中.窄缝消能工水力设计中几个问题的研究[J].西安理工大学学报,1987,3(2):73.
[11]宁利中,戴振霖.窄缝挑坎收缩段急流冲击波及其控制水深的计算[J].西安理工大学学报,1992,3(3):198.
[12]杜兰,黄国兵,王春龙.窄缝急流冲击波与水舌扩散规律研究[J].长江科学院院报,2013,30(8):55.
[13]MINOR H E,HELLER V,HAGER W H,et al.Ski Jump Hydraulics[J].Journal of Hydraulic Engineering,2005,131(5):347-355.