Analysis of the flow force compensation in relief valves with conical poppet

The paper deals with experimental tests and numerical simulations (3D and 0D fluid-dynamic modelling) of a conical poppet pressure relief valve with flow force compensation. The aim of the study was to realize a dynamic model of the valve, able to consider the effect of the pressure force, which arises downstream the metering edge and is determined by both the flow forces and the pressure recovery on the flow deflector. Starting from a 3D-CFD model, it was possible to study the interaction between the poppet opening and the pressure field, in order to evaluate the total pressure force as a function of the poppet displacement. The contribution of the pressure recovered on the deflector was separated from the traditional flow force and then parametrized as a function of some geometric features. It was then possible to develop a 0D fluid-dynamic model that is suitable not only for the considered valve but also for valves with similar geometries. Lastly, the model was validated using experimental data acquired on test bench for three different valves. The comparison of the predicted flow-pressure characteristics with the experimental ones indeed showed a good result matching. This model can also lead towards design considerations to study the behaviour of a larger number of valve geometries.