Numerical Simulation Research of Butterfly Valve in Acoustics Field Variation Characteristics

Abstract

A numerical simulation research was carried out on vortex and sound pressure level of the butterfly valve in the flow process based on FLUENT, which analyzed the variation of the vorticity and sound pressure level at different opening angles. There was an inverse pressure gradient in the orifice formed by the butterfly plate and pipe, which caused partial particle reflux on the back of butterfly plate in flowing, thus formed the vortex. The vortex formed on the back of the butterfly plate was decreased gradually, with the increasing opening angle of the valve in opening process. The noise was generated by the vortex separated and rupture in flowing. And the sound pressure level on the back of butterfly plate was decreased with the increasing opening angle. At the same time, the vorticity and the maximum sound pressure level position moved from the center to the rotation center of butterfly plate in opening process. The expanding orifice formed by butterfly plate upstream and the pipe and the tapered orifice formed by butterfly plate downstream and the pipe had the different throttling action to the fluid, which made the sound pressure level of upstream was higher than that of downstream in symmetrical position. The vortex generated by the separation of boundary layer would cause vortex excited vibration between plate and fluid, and then resonance occurred. The studies were carried out in the vorticity and the sound pressure level on the downstream of butterfly plate, and the changing law of those was found. It would provide a basis theory for reducing noise and avoiding vortex vibration of butterfly valve.