不同型式空气阀的水锤防护效果研究

Research on the efficiency of water hammer protection by various types of air valves

空气阀是安装在输水管道上的水锤防护装置。空气阀型式和孔径选择不合适,会使空气进入管道不及时而引起汽化现象或管道内的空气快速排放而引起水柱分离再弥合的撞击。为了研究不同型式空气阀的水锤防护效果,运用瞬变流理论和特征线方法,建立空气阀边界条件;用Matlab软件进行数值模拟计算,比较了没有空气阀、单阀孔空气阀和双阀孔空气阀的水锤防护效果。进一步分析了使用双阀孔空气阀时,不同阀孔孔径对水锤防护效果的影响。计算结果表明:安装孔径合适的双阀孔空气阀可以同时达到减小瞬变负压和防止瞬变正压过高的目的。

Air valve is water hammer protection device installed at water transfer pipes or mains. Improper selection of air valve type and size could lead to the phenomenon of vaporization as the inflow of air entering into the pipes not in time,or the fast expulsion of air in the pipeline indu-cing the separation of water column and close the transient.In order to study the effect of water hammer protection by different types of air valve,the theory of transient and the method of char-acteristics are used to establish the boundary conditions of air vale in this paper.Matlab software is used to carry out numerical simulation calculation and to compare the effects of water hammar potection without airvalve and with single valve oriffice and double-criffice air valves.The effects of water hammar protection by different valves with different diameters are further analyzed when the air valves with double valve oriffice are used.The calculated results indicate installing the ap-propriate oriffice diameter air valve with double-valve oriffice can achieve reducing transient nega-tive pressure and prevent the excessive transiment positive pressure at the same time.