Numerical and experimental analysis of the cavitation and study of flow characteristics in ball valve

Abstract

Cavitation in ball valve was numerically investigated using Computational Fluid Dynamics (CFD) modeling and then validated against results gained through experiments. The experiment was carried out in an assembly unit of the automotive industry to analyze flow patterns. The effect of bubbles on other thermophysical properties of the fluid was also examined using the multiphase k-ϵ viscous model in ANSYS FLUENT. The impact of changes in inlet pressure on vapor fraction was visualized through simulations and validated against experimental data, cavitation was calculated via cavitation index equation. It was observed that cavitation values ranged from 0.51 to 0.84 through computational fluid dynamics and from 0.46 to 0.80 in the experiment. Moreover, fluctuations in Turbulence Kinetic Energy (TKE) in the fluid through the boundary layers in the valve region, deformation in fluid particles in the form of Strain Rate (SR), and variations in the value of Wall Shear Stress (WSS) of the valve's internal walls were also studied through numerical simulations. The results show the pressure just before the valve drops and result in cavitation. Besides, turbulence kinetic energy, shear stress on the walls of a valve, strain rate, and fluid velocity were gradually increased at inlet pressure resulting erosion in the ball valve.

Keywords

• cavitation
• ball valve
• multiphase flow
• vapor fraction
• numerical modelling