An Investigation of Butterfly Valve Flow Characteristics Using Numerical Technique

Abstract

Numerical analysis technique has become popular and reliable method in design of butterfly valves. It is possible to visualize and observe the flow characteristics around the valve and to estimate its performance. In this paper, a numerical simulation for flow of water past over a butterfly valve using commercial fluid dynamics software FLUENT, has been implemented. The study focuses on the investigation of the flow characteristic for the valve of 38 mm diameter fixed in 40 mm pipe diameter and 500 mm length. In the analysis, the positions of the disk were set to be 0° (fully opened), 20°, 30°, 55° and 75° and change of inlet velocities of 0.5, 1, 1.5 and 2 m/s. Velocity profile, pressure distribution, turbulence kinetic energy and turbulence intensity are the parameters used to present the characteristic of flow. From the results obtained, turbulence in flow starts at the edges of the valve disc and gets growing according to the specified case. These vortices and circulation region are generated always in downstream region behind the valve disc. They are formed due to contact between higher and lower velocities paths. It was found that the flow has a small effect with increasing closing angle till it reaches 55°, where the flow around the valve started to become highly turbulent. As the valve closing disc angle increases, the pressure becomes bigger and bigger. It’s suggested that butterfly valve should not be fixed or used near the fully closed angles