低扬程多起伏输水系统池-阀-支线联合水锤防护特性分析OA

Aiming at the problem of water hammer protection that requires positive pressure across the whole line under accidental pump when the low-head and multi-undulating water conveyance system with fork pipe stops the pump in an accident,a water conveyance system in Guangdong Province was taken as an example.The boundary condition calculation models for high-level pool,bifurcated pipe and variable frequency pump operation were established.The method of characteristics was used to solve and analyze the water hammer protection effects of two combined schemes:1)a butterfly valve downstream of pump combined with a surge tank;2)a high-level pool combined with a terminal flow regulating valve and a branch water diversion valve.The advantages of pool-valve-branch combined water hammer protection were discussed.Subsequently,the diameter of high-level pool and the closing schedules of butterfly valve,water diversion valve and flow regulating valve downstream of the pump were optimized based on multi-objective grey wolf optimizer algorithm.The results show that in the low-head multi-fluctuating pipeline,the high-level pool can form a hydraulic partition in the pressure sec-tion,effectively solving the problems of small head drop difference in the pressure section and negative pressure at the high point of the pipeline.The diameter of the high-level pool is negatively correlated with the maximum pressure of the pipeline.Increasing the closing time of the terminal flow regulating valve and the water diversion valve can reduce the maximum pressure.Compared with the initial scheme,the maximum pressure of the whole line is reduced by 17.69 m,the minimum pressure is also reduced by 0.27 m,and the volume of the high-level pool is reduced by 21.39%.Thus,it meets the requirements of water hammer protection,and improves the economy of water hammer protection meas-ures.