低水头非完全宽尾墩三维流场数值模拟
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摘要
为解决常规物理模型试验受观测手段限制难以全方位研究深尾水消力池内水力学参数的问题,借助RNGk-ε紊流模型结合VOF方法对比研究深尾水作用下平尾墩及非完全宽尾墩试验方案下游消力池内流场变化,并揭示非完全宽尾墩消能机理.研究结果表明:受溢流堰纵向长度及下游消力池内深尾水限制,平尾墩底流式淹没水跃逼近溢流堰顶,消力池内消能紊动不足,出池水流形成强烈二次水跃;非完全宽尾墩则束窄部分溢流堰闸室过流断面促使形成纵向拉伸挑射水舌,利用各相邻闸室非对称出闸水流、增强消力池内入池水流横向流速梯度和水位落差,加剧消力池内入池水流横向扩散、交汇,在消力池上游区域形成由底层至表层的大幅度立轴旋滚,显著增强消力池内能量耗散,降低出池水流流速,取得较好的消能效果.
Limited by measuring means,the conventional physical model test almost couldn′t comprehensively study the variation of hydraulics parameters in the deep tail water stilling basin.Based on the renormalization group(RNG)k-εturbulence model and the volume of fluid(VOF)method,the flow field variation in the deep tailwater stilling basin of the flat gate pier program and incomplete flaring gate pier program were respectively studied,and the energy dissipation mechanism of incomplete flaring gate pier was revealed.Research results show that restricted by the longitudinal overflow weir length and the deep tailwater in the stilling basin,the submerged hydraulic jump approaches weir crest in the flat gate pier program,leading to the insufficient energy dissipation turbulence in the stilling basin and strong secondary hydraulic jump outside the stilling basin.The incomplete flaring gate pier program restricts the overflow weir chamber width to result to the longitudinally stretched water jet,and the asymmetric water flow is utilized in the adjacent chamber to enhance the lateral flow velocity gradient and the water level drop.The large vertical axis rolling from the bottom to the surface is created in the upstream region of stilling basin by the intensified lateral diffusion and intersection,which significantly enhances energy dissipation in the stilling basin,inducing the flow rate of outlet water and achieving well energy dissipation effect.
Limited by measuring means,the conventional physical model test almost couldn′t comprehensively study the variation of hydraulics parameters in the deep tail water stilling basin.Based on the renormalization group(RNG)k-εturbulence model and the volume of fluid(VOF)method,the flow field variation in the deep tailwater stilling basin of the flat gate pier program and incomplete flaring gate pier program were respectively studied,and the energy dissipation mechanism of incomplete flaring gate pier was revealed.Research results show that restricted by the longitudinal overflow weir length and the deep tailwater in the stilling basin,the submerged hydraulic jump approaches weir crest in the flat gate pier program,leading to the insufficient energy dissipation turbulence in the stilling basin and strong secondary hydraulic jump outside the stilling basin.The incomplete flaring gate pier program restricts the overflow weir chamber width to result to the longitudinally stretched water jet,and the asymmetric water flow is utilized in the adjacent chamber to enhance the lateral flow velocity gradient and the water level drop.The large vertical axis rolling from the bottom to the surface is created in the upstream region of stilling basin by the intensified lateral diffusion and intersection,which significantly enhances energy dissipation in the stilling basin,inducing the flow rate of outlet water and achieving well energy dissipation effect.
引文
[1]谢省宗,朱荣林,李世琴,等,宽尾墩戽式消力池联合消能工的水利特性与水力计算办法[J].水利学报,1992,5(2):7-18.
[2]谢省宗,吴一红,陈文学,我国高坝泄洪消能新技术的研究和创新[J].水利学报,2016,47(3):324-336.
[3]安刚,苑希民,杨昌增,等.低水头消能防冲实验研究[J].天津大学学报,1997,30(4):500-506
[4]杨凡,王均星,陈帅,等,低弗劳德数水流辅助消能工空蚀问题研究[J].水力发电学报,2015,34(2):125-129.
[5]尹进步,梁宗祥,龚红林.宽尾墩三元水跃特性试验研究[J].水利学报,2011,41(11):1333-1338.
[6]李乃稳,许唯临,田忠,等.高拱坝表孔宽尾墩体型优化试验研究[J].水力发电学报,2009,28(3):132-138.
[7]Li Naiwen,Liu Chao,Deng Jun,et al.Theoretical and experimental studies of the flaring gate pier on the surface spillway in a high-arch dam[J].Journal of Hydrodynamics,2012,24(4):496-505.
[8]李福田,刘沛清,许唯临,等,高拱坝表孔宽尾墩对泄洪能力影响的试验研究[J].水利学报,2003,11:43-47.
[9]张挺,伍超,莫政宇,等,X型和Y型宽尾墩水利特性对比研究[J].水利学报,2007,38(10):1207-1213.
[10]胡耀华,伍超,张挺,等,X型宽尾墩掺气空腔影响因素分析[J].四川大学学报:工程科学版,2007,39(3):24-28.
[11]李中枢,潘艳华,韩连超,等,宽尾墩联合消能工体型选择及水力特性的研[J].水科学进展,2000,11(1):82-87.
[12]Hirt C W,Nichols B D.Volume of fluid(VOF)method for the dynamics of free boundarues[J].J Compus Phys,1981,39(3):201-225.
[13]廖柳霞,王韦,刘善均,等.宽尾墩后局部边墙对掺气效果的影响[J].四川大学学报:工程科学版,2014,46(2):13-16.
[14]邓军,许唯临,自掺气水流流速分布[J].水动力学研究与进展,2002,17(3):369-375.
[2]谢省宗,吴一红,陈文学,我国高坝泄洪消能新技术的研究和创新[J].水利学报,2016,47(3):324-336.
[3]安刚,苑希民,杨昌增,等.低水头消能防冲实验研究[J].天津大学学报,1997,30(4):500-506
[4]杨凡,王均星,陈帅,等,低弗劳德数水流辅助消能工空蚀问题研究[J].水力发电学报,2015,34(2):125-129.
[5]尹进步,梁宗祥,龚红林.宽尾墩三元水跃特性试验研究[J].水利学报,2011,41(11):1333-1338.
[6]李乃稳,许唯临,田忠,等.高拱坝表孔宽尾墩体型优化试验研究[J].水力发电学报,2009,28(3):132-138.
[7]Li Naiwen,Liu Chao,Deng Jun,et al.Theoretical and experimental studies of the flaring gate pier on the surface spillway in a high-arch dam[J].Journal of Hydrodynamics,2012,24(4):496-505.
[8]李福田,刘沛清,许唯临,等,高拱坝表孔宽尾墩对泄洪能力影响的试验研究[J].水利学报,2003,11:43-47.
[9]张挺,伍超,莫政宇,等,X型和Y型宽尾墩水利特性对比研究[J].水利学报,2007,38(10):1207-1213.
[10]胡耀华,伍超,张挺,等,X型宽尾墩掺气空腔影响因素分析[J].四川大学学报:工程科学版,2007,39(3):24-28.
[11]李中枢,潘艳华,韩连超,等,宽尾墩联合消能工体型选择及水力特性的研[J].水科学进展,2000,11(1):82-87.
[12]Hirt C W,Nichols B D.Volume of fluid(VOF)method for the dynamics of free boundarues[J].J Compus Phys,1981,39(3):201-225.
[13]廖柳霞,王韦,刘善均,等.宽尾墩后局部边墙对掺气效果的影响[J].四川大学学报:工程科学版,2014,46(2):13-16.
[14]邓军,许唯临,自掺气水流流速分布[J].水动力学研究与进展,2002,17(3):369-375.