SIMTEC used CFD to study the hydraulic oil flow inside a control valve. Depending on the value of the pressure, the valve opens automatically to relieve the hydraulic system, when the pre-defined limit is exceeded. The control screw at the top of the valve is regulated due to the action of mechanical springs. Due to the significant pressure drop at the small opening, the static pressure drops below the oil vapor pressure, causing cavitation phenomena.

The developed CFD model assumed a constant valve opening, to study the evolution of cavitation. The solution of the flow calculated the phase changes (evaporation – condensation) with a multiphase model. The study showed that cavitation can be divided in three stages, each characterized by a discrete frequency. These frequencies are directly linked to hydrodynamically-induced noise and may cause structural fatigue to the valve body.