【作者】 从枭；

【导师】 罗灿； 袁尧；

【作者基本信息】 扬州大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 前池和进水池均是排涝泵站中重要的进水建筑物,一旦池内流态紊乱,水泵的进水条件就会变得极差,进而导致水泵的效率下降。尤其是对于侧向进水泵站,前池和进水池内流态相比正向进水泵站会更加复杂、紊乱。因此,本文以实际工程为研究对象,开展双侧向进水泵站进水流态分析,并提出针对性流态优化措施。本文以东升堤排涝站为工程实际背景,基于三维数值模拟的技术,分析了排涝站三种运行水位工况下的前池及进水池流态。重点分析了设计运行水位时,直导流墩、V形导流墩、对称川形导流墩和立柱对前池流态的影响,并研究了三段式导流墩、三角形立柱以及隔板对进水池流态的影响。(1)运用大型商用软件CFX,对东升堤排涝站进水建筑物进行数值模拟。通过网格无关性分析,确定计算域网格总数为186万。选用RNG k-ε紊流模型,预测了泵站三种水位工况下的进水流动特性。现状方案三种水位工况下,前池存在大面积的回流区,并挤压主流,进水池侧壁处存在大范围的脱流区,池内流速分布极其不均匀。(2)针对前池存在的回流等不良流态,提出了直导流墩、V形导流墩、对称川形导流墩和立柱等流态优化措施。设计运行水位工况下,通过正交试验的方法,分析了 V形导流墩的几何参数和位置参数对前池流态的改善效果。在此基础上,进一步研究了对称川形导流墩和立柱对池内流态的影响。该方案下,前池流速分布均匀,大尺度回流区全部消失,相比原方案,进水池进口断面轴向流速均匀度最大提高了 71.51%,速度加权平均角最大提高了 45.22°。(3)针对进水池存在的旋涡等不良流态,提出了三段式导流墩、三角形立柱以及隔板等流态优化措施。在前池整流的基础上,研究了上述措施对进水池进水流动特性的改善效果。该方案下,进水池侧壁脱流区消失,水流平顺流向喇叭口,进水管前断面流速均匀度与原方案相比最大提高了 19.47%,速度加权平均角最大提高了 15.74°。(4)最低运行水位时,最优组合方案下,池内回流区全部消失,水流平顺,进水管前断面流速均匀度最大提高了 23.67%,速度加权平均角最大提高了 12.11°。最高运行水位时,最优方案下,池内水流平顺,进水管前断面流速均匀度最大提高了 35.73%,速度加权平均角最大提高了 2.73°。本研究以已建成泵站为对象开展流态分析和优化研究,不仅具有实际工程意义,还可以为其他同类泵站提供参考。更多还原

【Abstract】 The forebay and sump are important intake structure for drainage pumping station,and if the inlet flow state is disordered,it will seriously affect the inlet conditions of the pump and reduce the efficiency of the pump.Considering the lateral inlet pumping station,the flow disorder of forebay and sump is complex.Therefore,this paper takes the actual project as the research object,carries out the analysis of the inflow flow state of the double lateral inflow pumping station,and proposes targeted flow state optimization measures.In this paper,taking the Dongshengdi drainage station as the actual background of the project,based on the technique of three-dimensional numerical simulation,the flow state of the forebay and sump of the drainage station under the three operating water level conditions are analyzed.The influence of V-shaped diversion piers and matrix circular columns on the flow state of the forebay during the design and operation of the water level is analyzed,and the effects of the three-stage diversion pier,triangular column and partition on the flow state of the sump are studied.(1)Using large-scale commercial software CFX,numerical simulation of the water inlet building of the Dongshengdi drainage station.Through mesh independence analysis,the total number of computational domain meshes was determined to be 1.86 million.The RNG k-s turbulence model was selected to predict the hydraulic performance of the pumping station under three water level conditions.When there is no rectification measure,under the three water level conditions,the flow state in the forebay is disordered,there is a large area of return flow area,and the main stream of the diversion channel is squeezed,and there is a large-scale deflow area at the side wall of the sump,and the flow rate distribution is extremely uneven.(2)Aiming at the unfavorable flow regimes such as backflow in the forebay,flow regime optimization measures such as straight diversion piers,V-shaped diversion piers,symmetrical river-shaped diversion piers and vertical columns are proposed.Under the designed operating water level condition,the improvement effect of the geometric parameters and position parameters of the V-shaped diversion piers on the flow state of the forebay is studied by means of the orthogonal test.On this basis,the improvement effect of symmetrical river-shaped diversion piers and columns on the flow regime in the pool was further studied.Under this scheme,the flow velocity of the forebay is evenly distributed,the large-scale malignant reflux area disappear,compared with the original scheme,the axial velocity distribution uniformity of the outlet section is increased by 71.51%,the average angle of speed weighting is increased by 45.22°.(3)Aiming at the unfavorable flow state such as backflow existing in the inlet pool,flow state optimization measures such as three-section diversion piers,triangular columns and baffles are proposed.Based on the rectification of the front pool,the improvement effect of the above measures on the flow characteristics of the inlet water in the inlet pool was studied.The deflection area of the side wall of the sump disappears,the water level flows downstream to the horn port,the axial velocity distribution uniformity of the front section of the horn mouth is increased by 19.47%,and the maximum speed weighted average angle is increased by 15.74°.(4)When the minimum operating water level is performed,under the optimal scheme,the return area in the pool disappears completely,the water flow is smooth,the axial velocity distribution uniformity of the front section of the inlet pipe is increased by 23.67%,and the average angle of speed weighting is increased by 12.11°.At the highest operating water level,under the optimal scheme,the water flow in the pool is smooth,the axial velocity distribution uniformity of the front section of the inlet pipe is increased by 35.73%,and the average angle of speed acceleration is increased by 2.73°.This study takes the built pumping station as the object to carry out flow analysis and optimization research,which not only has practical engineering significance,but also can provide reference for other similar pumping stations.更多还原