Reduction of the flow forces in a small hydraulic seat valve as alternative approach to improve the valve characteristics

In this paper the optimization of the spool and housing geometry in a small hydraulic seat valve to enable the reduction of the axial flow forces to a minimum value is described. Non-optimized hydraulic valve geometry is usually the main cause for many problems related to response time, actuation force and energy consumption. To overcome these limitations and problems we have done a thorough numerical and experimental analysis of a seat valve. The main influential geometry parameters of the seat valve are defined for numerical analyses. In the next step the basic theory of the numerical simulation, including the 3D modelling, meshing and parameterization, is explained. The reduction of the flow forces in a small hydraulic seat valve is treated in detail by using a commercial simulation tool, Ansys CFX. The validation of the numerical fluid model of the valve is done by comparing simulation and experimental results obtained with the test rig for axial flow force measurement. With the validated numerical fluid model of the valve new fluid models are built taking into account all influential geometry parameters of the valve for the purpose of the final optimization of the valve geometry. The results of the simulation analyses show that the axial component of the flow forces can be reduced significantly just by modifying the geometry of the valve spool and housing. Thus the valve dynamic characteristics, such as response time, are significantly improved while the necessary actuation force and power consumption are reduced.