梯级泵站事故停机输水明渠水力过渡过程研究

Study on Hydraulic Transition Process of Open Channel in Long-Distance Pumping Station

为解决梯级泵站系统因超负荷、大流量、高水位运行出现垮渠、跳闸停机等事故,而导致水力过渡过程中出现进水前池被抽干或漫顶等问题,以甘肃省景泰川电力提灌二期工程长距离输水明渠为研究对象,在多梯级泵站事故停机产生溢流的工况下,基于Realizable k-ε和VOF模型进行数值模拟计算,分析景电二期工程1#~7#干渠在调蓄系统作用下,不同渠长、坡降的水面线以及水力振荡分布规律。结果表明:泵站停机后水位出现升降交替的水力振荡现象,影响各泵站波峰水位高度不一致的主要原因是渠道坡降;不同参数特征的渠道壅水波运动的回溯距离不同,溢流堰上发生溢流的时间主要在第一次水位振荡过程中。

Due to overload,large flow and high water level operation,the cascade pumping station system has such accidents as canal collapse and tripping and stopping,and the water delivery system has entered the hydraulic transition state from the constant flow state,and the hydraulic transition process will cause the problems such as the draining or overtopping of the water inlet basin,which seriously threatens the safety of the plant and equipment of the pumping station.Based on Realizable k-ε model and VOF model,this paper took the long-distance open channel of Jingtaichuan Electric Power Irrigation PhaseⅡProject in Gansu Province as the research object.Under the working condition of overflow caused by the accident shutdown of multi-step pumping station,numerical simulation was carried out to analyze the different channel lengths,the water surface line of the slope and the distribution rules of hydraulic oscillation under the action of regulation and storage system of the No.1 to No.7 main channels of Jingtaichuan Electric Power PhaseⅡProject.The results show that the hydraulic oscillation of the water level after the pump station is shut down occurs alternately,and the main reason for the inconsistency of the peak water level is the slope of the channel.The backtracking distance of obstructing waves in different channels is different,and the overflow time on the overflow weir is mainly during the first oscillation of water level.