大流量倒虹吸水力特性研究

Study of Hydraulic Characteristics of Inverted Siphons with Large Flows

为保证大流量倒虹吸能够安全稳定的输水,采用流体动力学软件(CFD)对某工程三维数学模型进行数值模拟,并结合物理模型试验,分析了倒虹吸充水过程中水流变化特点和稳定后的水力特性。结果表明,倒虹吸水流流速最大位置位于管道下坡段,压强最大位置位于管道水平段;充水过程中,倒虹吸边部管道内水流流速较中部水流大8%左右;在水流稳定后倒虹吸下游闸室后存在卡门涡街现象,造成水流流态紊乱,导致下游水面震荡,需要对下游闸墩进行延长或进行墩头结构优化,以减轻涡街强度和水面震荡的影响。

In order to ensure large-flow inverted siphon can transport water safely and stably,fluid dynamics software(CFD)was used to numerically simulate a three-dimensional mathematical model of an engineering.Physical model tests was used to analyze the characteristics of water flow change during inverted siphon filling and stabilized hydraulic characteristics.The results show that the maximum position of the inverted siphon flow velocity is located in the downhill section of the pipeline,and the maximum position of the pressure pressure is located in the horizontal section of the pipeline.During the water filling process,the water flow velocity in the inverted siphon edge pipeline is about 8%larger than that in the middle water.After the water flow was stabilized,there was a Karman vortex street phenomenon in the downstream lock chamber of inverted siphon,resulting in water flow disorder and downstream water surface oscillation.So,it is necessary to extend the downstream gate pier or optimize the pier head structure to reduce the vortex strength and the influence of water surface oscillation.