为研究溢洪道弯段布置糙条消能工的消能特性,在新疆“635”溢洪道整治工程的研究基础上,通过量纲分析,建立了糙条消能率多因素影响模型;采用正交试验原理,对溢洪道弯段糙条消能工的布置进行正交试验并根据试验结果进行多重回归分析,得到了反映糙条布置参数和溢洪道工程参数的消能率计算公式;然后为探究各因素影响大小进行了相关性分析,并定义无量纲因子k来反映糙条消能工的综合特性。结果表明:溢洪道工程参数对消能率的影响较大,而糙条布置参数除布置角度外影响均较小;无量纲因子k与消能率和水面横比降均呈负相关关系,且改变糙条布置参数对水面横比降的影响较消能率大;k值的波动范围在0.016~0.049之间,当消能率最大时,k=0.025,水面横比降最小时,k=0.037。提出的消能率多因素影响模型是一种半理论半经验计算公式,可为实际工程设计提供理论依据。

To obtain the energy dissipation characteristics of rough strips arranged in the bends of spillway, a multi-factor influence model of the energy dissipation rate of the rough strips was established based on the research of the Xinjiang “635” spillway rectification project via dimensional analysis. According to the principle of orthogonal experiment, orthogonal test was conducted on the layout of the rough strip energy dissipator in the spillway bend, and multiple regression analysis was accomplished according to the test results to derive the calculation formula of energy dissipation rate reflecting the layout parameters of rough strips and the engineering parameters of the spillway. Moreover, correlation analysis was carried out to explore the influence of each factor, and a dimensionless factor <i>k</i> was defined to reflect the comprehensive characteristics of the rough strip energy dissipator. The findings are concluded as follows: the engineering parameters of spillway have remarkable impact on the energy dissipation rate, while the layout parameters of rough strips have little effect except for the arrangement angle. The dimensionless factor <i>k</i> was in a negative correlation with the energy dissipation rate and the transversal slope of water surface. In addition, changing the layout parameters of rough strips exerted a greater impact on the transversal slope of water surface than the energy dissipation rate. The value of <i>k</i> ranged between 0.016 and 0.049. When the energy dissipation rate reached the peak, <i>k</i>=0.025; when the transversal slope of water surface hit the bottom, <i>k</i>=0.037. As a semi-theoretical and semi-empirical calculation formula, the proposed multi-factor influence model for energy dissipation rate could offer theoretical basis for actual engineering design.

为探究糙条消能工在连续弯段溢洪道上导流效果影响因子排序和糙条导流特性,采取9因素3水平的正交试验设计方案进行物理模型试验,引入超高变异系数C_v对导流效果进行评价;对影响水流结构的因子进行量纲分析及多元回归处理,建立评价导流效果的多因素影响模型。结果表明:糙条布设角度和糙条高度分别对2个弯段中水流结构影响最大,这2个因素直接影响糙条平衡水面差、稳定流态效果的优劣。剔除影响较小的共用因素,得出糙条消能工最优导流布置方案;各类函数模型中最大拟合优度为0.822,拟合方程对实测值进行对比验证,二者相对误差范围在2.78%~7.15%之间。研究成果可为连续弯段溢洪道整流分析提供理论参考。

明渠陡槽加墩是一种高效消能工布置方式,在特定条件下具有很高的技术竞争优势,但目前国内相关研究甚少。针对甘肃庆阳小崆峒沟雨水下塬排放工程的明渠陡槽加墩段进行了1∶30大比尺水工模型试验研究,试验发现初步方案沿程水流流态不稳定,存在向外泼溅溢出现象,危及黄土边坡的结构稳定。为此对初步方案进行了优化研究,试验发现,通过缩短消能墩排距,可以显著减小水面波动,使沿程水深分布均匀,流速降低,沿程不再出现水流向外泼溅溢出现象。消能墩排距由H/i缩短至0.5H/i后,在最大设计流量工况下,水面波动减小72.5%,平均流速降低40.1%,总消能率由87.9%提高至94.6%。

针对大单宽流量、低弗劳德数消力池内消能问题,通过物理模型试验方法,对比分析消力池内加设梯形墩和悬栅消能工后水力特性和消能效果,优化梯形墩-悬栅消力池布置形式。结果表明:在低弗劳德数水流条件下,梯形墩-悬栅联合消能工断面水深分布均匀,消力池底板沿程压力分布梯度和时均压力分布系数波动幅度较小,整体稳定性较优;动能修正系数基本保持在1＜α＜2的范围内,可有效改善入池断面流速分布;消能率由传统消力池的52.25%、70.37%、75.89%分别提升至56.74%、75.95%、79.22%;梯形墩-悬栅消力池内悬栅单排等间距、高度与尾坎同高布置时,梯形墩呈双排交错形式布置在距池首0.35L左右处对于整体流态改善明显,消力池出口流速可降至0.4 m/s,消能率提高至59.63%、76.12%、79.37%,研究结果可为同类工程的底流消能问题提供一种新思路。

The layout form of trapezoidal pier and suspension grid in stilling basin is optimized through comparative analysis of the hydraulic characteristics and energy dissipation effect in the presence and in the absence of trapezoidal pier and suspended grid in stilling basin via physical model test. Results show that under the condition of water flow of low Froude number, the trapezoidal pier-suspended grid joint energy dissipator could generate uniform water depth distribution, smaller fluctuation range of pressure distribution gradient along the stilling basin floor and time-averaged pressure distribution coefficient, and better overall stability. The kinetic energy correction coefficient basically maintained in the range of 1 &lt; <i>α</i>&lt; 2, which can effectively improve the velocity distribution at the section of pool entrance. The energy dissipation rate increased from 52.25%, 70.37% and 75.89% to 56.74%, 75.95% and 79.22%, respectively. With the trapezoidal pier at about 0.35 L away from the head of stilling basin with staggered double row when the height of suspension grid is the same as that of tail ridge and arranging in single rows at equal spacing in the trapezoidal pier-suspension grid stilling basin, the overall flow pattern improves obviously, the flow rate at the outlet of stilling basin reduces to 0.4 m/s, and the energy dissipation rate increases to 59.63%, 76.12% and 79.37%. The research results offer an idea for the underflow energy dissipation of similar projects.