Analysis of safety valve characteristics using measurements and CFD simulations

In order to study valve characteristics, experiments of the Institut für Strömungsmechanik at the Technical University Hamburg-Haburg (TUHH) were used to validate the CFD-code ANSYS CFX. Due to the constant improvement of the physical models and numerics of the code it is now possible to simulate very complex flows through valves. This includes phenomena like jets, flow around obstacles, flow separation effects, stagnant regions and partly zones with high mach numbers. The geometric details of the safety valve internals have a strong influence on the flow field. Therefore, an exact representation of the inlet region, the seat and disc region and the shape of the valve body were necessary. The computational grid contains one million nodes. For code validation purposes experiments were taken with different fluids and mixtures and the influence of the different hubs was studied. In all cases a good agreement between measurements and numerical results could be achieved with existing models of the CFD code.