泵站虹吸式出水管虹吸形成时间特性分析及其改善措施

Analysis on siphon formation time characteristics and improvements for siphon outlet conduit in a pump station

由于虹吸式出水管虹吸形成时间的长短直接影响泵站能否安全稳定运行,为研究虹吸形成时间特性及虹吸管改善措施对虹吸形成时间的影响,采用RNG k-ε湍流模型和结构化网格对某一泵站虹吸式出水管进行数值模拟。数值模拟结果表明:水力驱气阶段持续时间与进流流量有关;水力挟气阶段排气速率与水气交界面处流速大小有关;虹吸形成过程中上下气囊的产生对于虹吸形成十分不利,在驼峰顶部设置分流板能有效改善虹吸管内流速分布,加速顶部气囊的排出,缩短虹吸形成时间,且对水力损失影响极小。

The safety operation of a pump station is directly affected by the siphon formation time of a siphon outlet pipe. In order to investigate the siphon formation time characteristics and the impact of the improvement on siphon formation time,RNG k-ε turbulence model with structured grids were used to simulate the siphon outlet pipe of a pump station. The numerical simulation results show that the duration of the hydrodynamic phase is related to the inflow flux. In the hydroponic phase,the exhausting rate is related to the velocity at the water air interface. During the siphon formation process,the generation of airbags is very unfavorable for the siphon formation and configuration of a splitter plate at the top of the hump section can effectively improve the flow rate distribution in the siphon,which can accelerate the discharge of the airbags,shorten the siphon formation time and minimize the influence on the hydraulic loss.