排气阀在山地灌溉管道中的水锤防护作用

Water Hammer Protection Effect of Air Evacuation Valves in Mountain Irrigation Pipe System

建立山地灌溉管道模型，通过试验量测管道瞬时压力，对比安装排气阀前后管道凸起段在球阀快速关闭瞬间的压力变化。得出不安装空气阀，球阀快速关闭时管道凸起部位各段水锤压力在振幅范围内快速波动，振幅呈现递减趋势，一定时间后趋于稳定；安装排气阀后突起部位各段（坡后段除外）最大水锤压力值明显降低，降幅在40％～50％之间，但最小值小于不安装排气阀时的值，整体振幅没有变化，水锤压力在振幅范围内快速波动。

In this paper, the mountain irrigation pipe system model is established and the pipe instantaneous pressure is measured through test to compare the salient point pressure change during the ball-valve quickly turning-off process under the conditions that the air evacuation valve is installed or not. The results show that under the condition that the air evacuation valve is not installed, the water hammer pressure in the salient point fluctuates rapidly in the amplitude range, the amplitude shows decreasing tendency and tends to be stable after a certain period of time. While under the condition that the air evacuation valve is installed, the water hammer pressure in the salient point decreases significantly by 40% to 50%, but the minimum is less than the one without air valve, the whole amplitude has no change, the water hammer pressure fluctuates rapidly in the amplitude range.