PVC球阀对山地灌溉管道水锤特性的影响

Effect of PVC exhaust valves on water hammer protection of mountain irrigation pipes

【目的】研究PVC球阀快速关闭时灌溉管道凸起部位的水锤压力特性,为灌溉输水管道工程管理及其优化设计提供依据。【方法】建立山地灌溉管道模型,通过室内研究,测定并分析凸起管道不同位置PVC球阀快速关闭对水锤压力的影响。【结果】(1)球阀快速关闭时,关阀前流量越大,凸起部位各坡段的水锤压力最大值均越大;(2)流量相等且关闭时间相同时,凸起部位上游球阀关闭时的水锤压力最大值大于下游球阀关闭的最大值;(3)流量相等的条件下,同一球阀关闭时,凸起部位各管段水锤压力随时间的变化规律相似;(4)流量相等,关闭时间相同时,凸起部位上游球阀关闭时的水锤压力递减速率大于下游球阀关闭时的水锤压力递减速率。【结论】事故工况下,优先选择关闭凸起部位下游球阀,优化设计中球阀位置应尽量远离凸起部位。

【Objective】This research studied the water hammer pressure characteristics of irrigation pipeline convex parts when PVC ball valve was closed quickly to provide basis for irrigation water pipeline project management and optimal design.【Method】Mountain irrigation pipe model was built and effects of different positions PVC ball valves on water hammer characteristics of the pipeline convex parts were investigated through indoor experiments.【Result】(1)When the ball valve was quickly closed,the greater the flow before closing the valve,the bigger the maximum water hammer pressures of different slopes of the raised part.(2)When the flow and the closing time were the same,the maximum value of the water hammer pressure of upstream valve convex position was greater than that of the downstream valve.(3)When the flow was equal,for the same valve,water hammer pressure variation of each pipe section along with time was identical.(4)When the flow and the closing time were equal,the decline rate of water hammer pressure of upstream valve convex parts was greater than that of the downstream valve.【Conclusion】Convex parts downstream valve should be preferentially closed when accident happens.The valve position should be as far as possible away from the convex part in optimization design.