空气阀型式对压力管道水锤防护的影响

Impacts of type of air valve on water hammer protection in pressurized pipelines

针对目前空气阀在工程应用中的盲目性和随意性,对各种型式空气阀在有压管道中水锤防护进行数值模拟,为空气阀在实际工程应用中的选型提供理论依据.根据水锤理论,建立有压管道水力过渡过程数学模型.结合算例利用特征线法对各种空气阀在有压管道中的水锤防护效果进行数值计算.结果表明:管道凸起点安装传统空气阀可以减小负压,但是同时会引起较大正压;安装孔口面积比ε=0.05~0.20的空气阀组可以有效减小负压并降低正压,上浮压力系数ω接近1.0的防水锤型空气阀也可以起到减小负压,降低正压的作用.选择合理型式空气阀,并对空气阀的参数进行优化,可以显著降低管道内负压,并能防止水柱分离再弥合水锤现象发生.

There is blindness and randomness in using air valves in engineering application at present,hence water hammer protection in pressurized pipelines is simulated numerically for various types of air valves to establish some theoretical guidance for selection of air valve in application. According to theory of water hammer,a hydraulic transient mathematical model was built for pressurized pipelines. The effects of air valves on water hammer protection were predicted numerically in pressured pipelines by using the method of characteristics and by employing a few of examples. The results show that a traditional air valve installed at the pipeline high point can reduce negative pressure and cause excessive pressure.The set of air valves with orifice area ratio ranged in 0. 05-0. 20 can reduce the negative pressure effectively and decrease the excessive pressure. The anti-slam air valve with 0. 05-0. 20 orifice area ratio and nearly 1. 0 floating pressure coefficient can reduce the negative pressure and can decrease the excessive pressure. Properly selecting air valves and optimizing their parameters can reduce the negative pressure in a pressurized pipeline significantly and prevent column separation to occur.