泵系统中柔性阀门漏水引起的自激振动分析

Analysis of self-excited vibration caused by leakage of flexible valve in pump system

为了研究阀门的漏水过流特性及自激振动机理,应用特征线法对供水工程泵系统中柔性阀门漏水引起的自激振动进行分析,得到阀门上游测压管水位随时间的变化曲线.通过改变该泵系统的管长、管材与阀门漏水流量等,形成2个对比方案并进行数值模拟自激振动过程.结果表明:管道的长度及管材对自激振动的幅值、周期以及振幅增长速率影响极大;阀门的漏水流量对自激振动的幅值及周期影响较小,但对系统的振幅增长速率影响较大.任由自激振动发展,将会导致爆管事故的发生.

To analyze the flow characteristics of leakage as well as the mechanism of self-excited vibration in valves,a method of characteristics was used to assess the effect of flexible valve leakage on the self-excited vibration in water-supply pump system. Piezometric head in upstream of the valve as a function of time was obtained. Two comparative schemes were proposed to simulate the process of selfexcited vibration by changing the length,the material of the pipeline and the leakage of valves in the above pump system. It is shown that the length and material of the pipe significantly affect the amplitude and cycle of self-excited vibration as well as the increasing rate of the vibration amplitude. In addition,the leakage of the valve has little influence on the amplitude and cycle of self-excited vibration,but has a significant effect on the increasing rate of vibration amplitude. A pipe explosion accident may occur without the inhibiting of self-excited vibration.