空气阀内部结构优化与水锤防护分析

Structural optimization and water hammer protection of air valve

空气阀能在事故工况时通过进气消除管线上的负压,但会因排气速度过快而引发更加严重的弥合水锤升压,因此对传统的高速进排气阀内部结构进行优化,增加了能减缓排气速度的缓冲阀瓣。利用计算流体力学(CFD)的数值模拟方法对结构优化后的空气阀进行数值模拟分析,模拟中通过改变进排气时的压差得到了空气阀的流量曲线。模拟结果表明:空气阀的流量系数与压差有关,而不是一个固定不变的值;采用孔口面积比为0.1的缓冲阀瓣能在排气阶段减缓排气速度,且不影响进气消除负压功能。通过工程算例验证了结构优化后空气阀的水锤防护效果优于传统的高速进排气阀。

Air valve can eliminate negative accident, but the excessive exhaust speed will pressure in pipeline by snifting air in the event ot an lead to more serious water hammer boost. To solve this problem, the internal structure of the traditional high-speed intake and exhaust value was optimized, and a buffer disc that slows down the exhaust speed was added. A CFD numerical simulation method was adopted to analyze the air valve after the structural optimization, and a flow curve was obtained by changing the pressure difference between air intake and exhaust. The results showed that the flow coefficient of the air valve was related to the pressure difference, not a fixed value. A buffer disc with an orifice area ratio of 0. 1 could slow down the exhaust speed during the exhaust phase without affecting negative pressure elimination function by air intake. Through an engineering example, it was proved that the water hammer protection effect of the structure-optimized air valve was better than that of the traditional high-speed air valves.