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长距离输水管道为了补 (排 )气需要安装气阀 ,气阀工作时在阀附近的管道内会形成空穴 ,并且以气阀为中心 ,上下游管系、空穴和气阀组成一个局部的小系统 ,形成管系水流特性、空穴参数和过阀气流特性的连续同步变化 ,并使管内出现振荡流动 .本文通过计算实例对过阀气流参数按等熵流动过程计算 ,空穴参数按等温过程计算 ,上、下游管系内的水流特性则按非定常流动计算 ,其计算结果基本符合实际情况 .由此得到的过阀气流的质量流量 ,可用于选择气阀的过流面积 ,而管系内水流的振荡流动特性 ,可供管道系统设计、气阀布设安装时参考 .
In order to supplement (row) gas, long-distance water pipelines need to be installed with gas valves. When the gas valve works, holes will be formed in the pipe near the valve, and the gas pipe valve is used as the center, and the upper and lower pipelines, holes and gas valves form a part Of the small system, the formation of pipe flow characteristics, hole parameters and over the valve flow characteristics of the continuous synchronization changes, and the tube oscillation occurs.This paper through the calculation example of the valve flow parameters calculated by the isentropic flow process, the hole parameters by The calculation of isothermal process, the flow characteristics in the upstream and downstream piping systems are calculated according to the unsteady flow, and the calculation results are basically in line with the actual situation. The mass flow rate of the over valve flow thus obtained can be used to select the over flow area of the valve, Fluctuations and flow characteristics of water flow within the piping system for piping system design, valve installation reference installation.