ABSTRACT
Safety relief valves are well established components preventing catastrophic failure of
pressurised systems when non–normal operating conditions occur. However, it is only
recently with developments in CFD techniques that the capability to predict the complex
flow conditions occurring in the valves has been possible resulting in only limited
studies being found in the literature. This paper presents experimental and theoretical
investigations applied to a safety relief valve designed for the refrigeration industry but
extended here to consider pneumatic systems since air is the compressible fluid. The
discharge flow rate and valve forces are determined both theoretically and
experimentally for different valve lift conditions and related to the detailed flow
conditions (pressure, temperature and Mach number) in the valve predicted by CFD
techniques. The CFD code FLUENT has been used with a two dimensional
axisymmetric RANS approach using the k-ε turbulent model to predict the highly
compressible flow through the valve. The model has been validated by comparison with
experimental measurements and the predicted results show good agreement, providing
confidence in the use of CFD techniques for valve design and improvement.