事故停泵工况下蝶阀关闭规律对并联大型离心泵组的水锤影响研究

The Influence of the Closure Law of the Hydraulic Butterfly Valve on the Water Hammer of the Accident of the Parallel Group of Large Centrifugal Pumps

泵后蝶阀是泵站水锤防护的重要装置,采取合适的关阀规律是降低事故停泵时水泵最大反转转速和管线最大压力,保证水泵安全运行的关键,本文以犬木塘输水工程为研究对象,利用一维特征线法对事故停机水锤进行数值模拟计算,分析了液控蝶阀线性关闭规律与两阶段关闭规律对并联大型离心泵组的影响。采取控制变量法,分别以快关时间、慢关时间、快关阀门关闭量作为变量着重分析了两阶段关闭规律下供水系统最大压力和水泵最大反转转速的变化,通过比较2泵同停和1泵运行1泵停止工况下停泵水锤,得到了最佳的关阀规律。结果表明:相比于线性关闭规律,合适的两阶段关闭规律能显著降低管线最大压力,减少水泵最大反转转速,影响水泵最大反转转速的主要因素为快关阀门关闭量,次要因素为阀门快关时间和阀门慢关时间;在合适的阈值内快关阀门关闭量越大、阀门快关时间越短、阀门慢关时间越短为最佳的两阶段阀门关闭规律。

Taking the Quanmutang water conveyance project as an example,the one-dimensional characteristic line method was used to numerically simulate the water hammer of the accident shutdown,and the influence of the linear closing law and the two-stage closing law of the hydraulic butterfly valve on the water hammer of the accident shutdown pump in the parallel group of large centrifugal pumps was analyzed.The control variable method was adopted to analyze the changes of the maximum pressure of the water supply system and the maximum reversal speed of the pump under the two-stage closing law by taking the fast closing time,slow closing time and fast closing valve closing amount as variables,and the optimal valve closing law was obtained by comparing the water hammer of the pump stop under the condition of 2 pumps stopping at the same time and 1 pump running and 1 pump stopping.The results show that compared with the linear closing rule,the appropriate two-stage closing law can significantly reduce the maximum pressure of the pipeline and the maximum reversal speed of the pump,and the main factors affecting the maximum reversal speed of the pump are the closing amount of the fast-closing valve,and the secondary factors are the fast-closing time of the valve and the slow-closing time of the valve.Within the appropriate threshold,the larger the fast-closing valve,the shorter the fast-closing time and the shorter the slow-closing time of the valve,the optimal two-stage valve closing rule.