Janusz Rajda

The paper presents an analysis of switching time for pilot operated directional control valve [1–3] in a typical hydraulic system, in which the actuator is a hydraulic cylinder. A mathematical model has been built which contains equations of motion for the valve and actuator components, the balance of fluid flow, flow through the gap, and the principle of conservation of momentum and the flow curves of pressure relief valves [6, 8]. The system of equations is solved by fourthorder Runge-Kutta method. A survey to find minimal switching time has been conducted [4]. Positive overlap value, the coefficient of its movement resistance and control pressure value have significant impact on the switching time in the tested valve.

The paper presents a CFD analysis of flow forces acting on a spool of directional control valve type WE10J. This is a four-port, three-position, solenoid directly operated valve with a nominal diameter of 10 mm and working pressure up to 35 MPa. The aim of the study was to investigate whether hydraulic forces acting on the spool during the flow of working fluid through the valve could be reduced by changing the geometry of that spool. ANSYS/Fluent software was used for the CFD analysis.

W artykule przedstawiono ocenę możliwości obniżenia strat ciśnienia przy przepływie przez rozdzielacz
hydrauliczny WEH22. W tym celu zbudowano modele 3D dróg przepływowych, które wygenerowano za
pomocą programu CREO Parametric, a następnie te modele wykorzystano w programie ANSYS/Fluent do obliczenia strat ciśnienia. Uzyskane wyniki analiz pozwoliły na określenie możliwości obniżenia strat ciśnienia bez zmian wymiarów gabarytowych korpusu rozdzielacza.

This paper presents a method with the use of CFD analysis for calculating the forces acting on the spool during the flow of working liquid stream through the electro-hydraulic pilot operated directional control valve. The liquid stream flowing through the directional valve causes hydrodynamic response according to the principle of conservation of momentum. Liquid pressure acting on the spool surface affects the forces balance of valve spool as well. An object of the research is the pilot operated directional control valve WEH22 type with flow rate up to 450 dm3/min. For the analysis ANSYS/Fluent software was used.