Computational Fluid Dynamics Investigations of Shock Waves in Safety Relief Valves

Abstract

Safety Relief Valves plays an important role in any pressurised system. The proper design of safety relief valves should consider the eective opening and closing characteristics to achieve the desired valve performance. One of the challenges in any valve design is the elimination of Shock waves. Shock waves are characterised by sudden pressure increase and Mach number drop. Detecting shock waves in safety relief valves using computational uid dynamics could asses valve design to eliminate the shock waves. I t have been proven that the Reynolds Averaged Navier Stocks (RANS) equations with the k-turbulence model could model the internal gas ow in safety relief valves. The RANS and k-turbulence have been solved by a commercial CFD code. In safety valves discharge ow rate and closing and opening behaviours depend on the upstream pressure and certain critical areas. In this study, the eect of the upstream pressure has been discussed. Upstream pressure range was from 7 to 140 bars. The eect of the valve geometry has been discussed as well. Dierent critical outlet areas and divergent angles have been changed to investigate its eect on the shock wave parameters. The upstream pressure eect on shock wave occurrence and intensity have been studied. The results showed that, computational uid dynamics can be used to predict the location of the shock wave. In addition to determining the pressure peak and the Mach number drop and other properties which help eliminating shock wave occurrence in valve design. An ecient design should consider the geometrical and ow parameters that aect the shock wave occurrence and intensity.