典型控流调压阀后突扩体的压力特性

Pressure characteristics of sudden expansion pipe behind typical regulating valves

为了研究突扩体对控流调压阀门的增压减振作用,以典型控流调压阀门(活塞式调流阀和固定式锥形阀)为研究对象,采用物模试验和三维数值模拟相结合的研究方法,重点对2类阀门在不同突扩体型、阀门开度及空化强度下的阀后流态及管壁压力特性进行了观测分析,探究突扩比与阀后稳定压力的定量关系,试验阀门通径为150 mm,阀门直径为150~370 mm,突扩体长度为1000 mm.结果表明,突扩体能提升阀后管壁时均压力、减弱压力脉动的基本原理是水垫层效应.综合物模与数模试验结果,拟合得到了突扩比与阀后管壁稳定时均压力的关系式.突扩体可以提升阀门的工作背压,提升程度随突扩比的增大而渐缓.当突扩比为4.00时,阀后管壁稳定时均压力的增幅已非常平缓,趋于稳定.不同阀型试验结果差异小,说明突扩体的增压减振作用具有普适性.研究结果可供输水调压工程阀门段管道系统设计参考借鉴.

In order to study the pressurization and deactivation effect of sudden expansion on the valve,the typical valves(plunger valve and fixed cone valve)were taken as the research objects,and a research method combining physical model test and three-dimensional numerical simulation was adopted to observe and analyze the flow pattern as well as the wall pressure characteristics of the two types of valves under different sudden expansion size,valve opening,and cavitation strength.Then the quantitative relationship between the burst expansion ratio and the stable pressure behind the valve was investigated on a test valve diameter of 150 mm,valve diameter of 150-370 mm,and a sudden expansion pipe length of 1000 mm.The test results show that the sudden expansion can raise the uniform pressure on the wall and weaken the pressure pulsation because sudden expansion will form water cushion.Based on the results of the physical test and numerical simulation,the relationship between the sudden expansion ratio and the time-average pressure on the wall was obtained by fitting.The sudden expansion can increase the working back pressure of the valve,and the promotion is gradually slow with the increase of the sudden expansion ratio.When the sudden expansion ratio is 4.00,the average pressure increase on the wall is very gentle and tends to be stable.The difference between the test results of different valve types is very small,which indicates that the supercharging and damping effect of sudden expansion has universal applicability.The research results can be used as a reference for the design of pipeline systems in the valve section of water conveyance and pressure regulation engineering.