超大型城市供水泵站前池导流措施的流场及水力模型研究

该文针对多种约束性条件下的大型泵站前池流态,通过建立紊流不可压缩流体的速度场模型及多方案的水力模型,运用有限体积法计算并分析了增设导流锥、导流墩对前池及吸水池流场的改善情况。数值模拟的计算结果表明,增加导流锥后,喇叭口下方水泵进水偏流角一般均小于4°,对改善进泵偏流效果显著;事故工况时,单侧吸水池的水泵平均流量偏差比由26.89%降低至13.26%,吸水管附近水流比较平顺、均匀。水力模型试验表明,泵站前池的八字形导流墩方案可有效地消除存在的大范围回流区和斜向流,并通过调整配水孔口的分流比加强导流作用;导流墩整流方案配水渠至前池末端最大水位落差为0.020m,满足设计方所提出的水力设计要求。

Study on Flow Field and Hydraulic Model of Fore-bay Diversion Measures for Super-large Urban Water Supply Pumping Station

Aiming at the fore-bay flow filed of large pumping station with multi-restriction,an incompressible turbulent fluid velocity field model and a multi-hydraulic model are established.The article calculates and analyzes the flow filed improvement of fore bay and suction tank with the additional diversion cone and diversion pier by the finite volume method.The calculation result of numerical simulation shows that the influent drift angle of pump below the inlet is generally less than 4° with the additional diversion cone,which is useful to improve the drift effect of influent pump.In accident conditions,the average flow deviation ratio of pump for unilateral suction tank is reduced from 26.89% to 13.26%,and the flow field near the suction pipe is smooth and uniform.Hydraulic model tests show that the splayed diversion pier scheme for the fore bay of pumping station can effectively eliminate a wide range of existing back-flow zone and oblique flow zone,and strengthen the role of diversion by adjusting the flow ratio of water distribution holes.The maximum water level drop between the water distribution channel and the end of fore bay is 0.020 m by diversion pier rectification scheme,which meet the design requirements of the hydraulic design.