Pressure characteristics of sudden expansion pipe behind typical regulating valves
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 expan-sion pipe length of 1 000 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 sud-den 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 re-sults 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.
万方数据
维普
