NUMERICAL AND EXPERIMENTAL INVESTIGATION OF CAVITATING FLOW IN OIL HYDRAULIC BALL VALVE

Abstract

The three-dimensional cavitating flow issuing from the orifice of a ball valve was numerically investigated using the combination of RNG k-ε turbulence model and multiphase flow model. The cavitation region was predicted for axisymmetric and non-axisymmetric case when the ball moves to one side. Flow visualization experiment was conducted to capture cavitation images near the orifice of the ball valve using high-speed video camera. The predicted and observed cavitation regions agree well. Furthermore, the noise spectrums of the ball valve in cavitation and non-cavitation cases were measured. The results show that the cavitation around the orifice occurs periodically with a very high frequency of 2500 Hz. The predicted cavitation region for axisymmetric and non-axisymmetric case was compared with experimentally visualized cavitation image. It was expected that the ball vibrates in the lateral direction and cavitation occurs periodically.