Modelling incompressible flow in a pressure relief valve

Abstract Lift, blowdown and discharge of pressure relief valves depend ultimately on the flow structures generated within those valves. A report is made of an enquiry into the incompressible flow structure within such a valve. Commercial software is used to predict axisymmetric flow patterns inside a model of a real valve, and comparisons are made with the pressure distribution and force imposed on the real valve disc. The reliability of the simulation is further assessed using the oil-film technique to record reattachment lengths of separated shear layers. Results of the simulation are encouraging and have enabled flow regimes visible in the valve flow characteristic to be identified with the transition between separated flow patterns inside the valve.