고제어 성능을 가진 버터플라이밸브의 개도각에 따른 유체유동에 대한 연구

Abstract

The objective of this study is to simulate valve flow coefficient and flow characteristics such as velocity and pressure distribution for butterfly valve. The size of the valve used in this study is 125A. The range of the valve opening angle was a=15°∼70°, and it was changed by 5°. At the range of a=15°∼30°, the valve flow coefficient  gradually increased, and after a=30°, it increased rapidly. In the range of a=20°∼70°, the pressure change in the -2.9cm∼+2.9cm region in the pipe greatly depended on the opening angle and the position within the pipe. However, after +2.9cm, the pressure at the rear end of the valve was shown to depend only on the opening angle. At a=20°, Vortex shedding occurred for the first time at time t=0.25sec and continuously occurred in rear end of the valve over time. After a=45°, in the flow pattern at the rear end of the valve, the upward flow at the lower end of the valve and the flow at the upper end met each other to form a mixed flow. This flow phenomenon was shown to form a more intense mixed flow in the rear end region as the opening angle increased. Vortex flow occurred for the first time at a=15°, and the opening angle increased, the occurrence and disappearance of this flow phenomenon occurred periodically according to the certain flow region. The pattern of the pressure distribution in the region at the rear end of the valve showed a tendency to agree well with the results of the vorticity distribution.