长距离有压输水系统空气阀排气流量系数研究

在长距离有压输水系统中,空气阀防护水锤的效果往往与其进排气流量系数密切相关,而通常在进行空气阀的进排气流量计算时认为进排气流量系数为常量。研究通过分析比较空气阀排气性能规范实测数据与理论计算结果,得出空气阀的排气流量系数是随着阀内外压差的变化而变化的,应是一动态的系数,且工程实例计算结果表明排气流量系数采用固定值和动态值得到的空气阀的进排气特性有明显差别,从而为更准确模拟长距离有压输水系统的水力过渡过程提供技术依据。

Research on Discharge Coefficient for the Outflow Orifice of Air Valve in Long Distance Pressure Water Delivery System

In the long pressure water delivery system,the effect of air valve for water hammer protection is often closely related with its discharge coefficient,and usually the discharge coefficient is regarded as constant when flow for outflow and inflow air valve is calculated.By the analysis and comparison between the measured data of exhaust performance of air valve and the result of theoretical calculation in this study,it concludes that the discharge coefficient for the outflow orifice,changing with the variation of pressure difference inside and outside of the air valve,it should be a dynamic coefficient,And the calculation result of the engineering example also shows intake and exhaust performance of air valve using a fixed discharge coefficient have significant differences with using a dynamic one,consequently provides technical support for more accurate simulation on hydraulic transition process in long distance pressure water delivery system.