泵站加压与重力自流联合供水工程的停泵水锤防护

针对某首部泵站加压与重力自流相结合的长距离、高落差输水工程，基于瞬变流计算中常用的特征线法建立了全系统水力过渡过程数学模型，模拟了系统停泵水锤全过程.为了解决水泵机组掉电后管道中出现的负压问题，提出了在泵后采用空气罐的防护方案，并对空气罐参数进行优化设计，确定了较优的空气罐体型；于管道最高点处设置高位水池，水池后的重力流段采用减压阀与调节池串联的方式进行消能.停泵工况下为避免高位水池漏空，需要关闭各个减压阀.为了防止关阀产生的升压水锤超过管道承压标准从而发生爆管事故，同时考虑到各调节池水位波动的影响，选择不同关阀方案进行对比.计算结果表明，本工程空气罐较优体积为15 m³,停泵后减压阀采用120 s一段直线关闭.由于减压阀后设置调节池，相继关阀和同时关阀对结果影响较小.研究结论为同类供水工程的设计和安全运行提供了参考.

Pump failure water hammer protection of pumping station pressurization and gravity combined water supply project

Aiming at the long-distance and high drop water conveyance project with the combination of pressurization and gravity gravity gravity flow in a head pump station, the mathematical model of the whole system hydraulic transition process is established based on the characteristic line method commonly used in transient flow calculation, and the whole process of pump shutdown water hammer is simulated. In order to solve the problem of negative pressure in the pipeline after power failure of water pump unit, the protection scheme of using air tank behind the pump is put forward, the parameters of air tank are optimized, and the better shape of air tank is determined; A high-level water tank is set at the highest point of the pipeline, and the gravity flow section behind the water tank adopts the mode of series connection of pressure reducing valve and regulating tank for energy dissipation. Under the condition of pump shutdown, in order to avoid empty leakage of the high-level water tank, it is necessary to close all pressure reducing valves. In order to prevent the booster water hammer generated by valve closing from exceeding the pipeline pressure bearing standard, resulting in pipe explosion accident, and considering the influence of water level fluctuation of each regulating tank, different valve closing schemes are selected for comparison. The calculation results show that the preferred volume of the air tank of the project is 15 m³, and the pressure reducing valve is closed in a straight line in 120 s after the pump is stopped. Since the regulating tank is set behind the pressure reducing valve, closing the valve successively and closing the valve at the same time has little impact on the results. The research conclusion provides a reference for the design and safe operation of similar water supply projects.