Control of Volumetric Flow-Rate of Ball Valve Using V-Port

The control of volume flow rate in a ball valve is very important when a ball valve is utilized in a piping system. It is difficult to linearly control the flow rate in a ball valve without external devices. V-ports are employed to achieve this purpose. In order to investigate the effects of V-port on the volume flow rate and flow features, 3-D numerical simulations and experiments were conducted to observe the flow patterns and to measure performance coefficients when V-ports with various angles were used in a piping system. Three V-ports with angles 30 deg, 60 deg, and 90 deg were studied. It was found that V-ports with angles 30 deg and 60 deg make the flow rate proportional to the valve opening. However, V-ports increase the pressure loss between the inlet and the exit of a ball valve. In addition, V-ports with a small angle such as 30 deg increase the possibility of cavitation compared with flows without V-ports.