The Influence of the Number of Finite Volumes and Mesh Refinement on Δp -q Characteristics in the Analysis of Hydraulic Oil Flow through the Chambers and Channels of Cylindrical Piston Distributing Valve

SUMMARY The developments in Computational Fluid Dynamics (CFD) during the last decade have enabled accurate and reliable calculation of velocity, pressure and temperature fields in fluid flow through different mechanical parts and systems. The quality of results numerically obtained depends on the quality of finite volume mesh, i.e. the number and type of finite volumes that are used in mesh generation. The numerical analysis of stationary oil flow through chambers and channels of cylindrical piston distributing valve was performed and this paper presents the influence of the number of finite volumes and mesh refinement on Δp-Q characteristics of the valve. 1. INTRODUCTION Cylindrical piston distributing valve is one of the most important control and regulating components of hydraulic systems. In classic hydraulics the main function of distributing valves is to control the flow of fluids. Additionally, in proportional and servo hydraulics distributing valves have a great influence on kinematic, dynamic and fluid pressure characteristics. The use of hydraulic fluid systems with classical, proportional and servo distributing valves is very common and important in industrial applications. Consequently, number of engineering and scientific investigations deal with the analysis of distributing valves, [1]. However, Computer Fluid Dynamics (CFD), i.e. numerical analysis of fluid flow through channels and chambers of cylindrical piston distributing valves and their operating performances has been used only in a few special cases. The analyses were performed on simple two-dimensional models using some of the special programs developed for simulations. For instance, A.Kilchmann used the finite difference method in his investigations. On the basis of R.N.Clark investigations, M.Y.Guo and K.Nakano used the boundary elements method to analyze the compensation of fluid force acting on a valve piston. Also, T.Tsukiji used numerical analysis in investigation and simulation of the fluid flow by discrete vortex method. In recent years many authors have used numerical methods such as Finite Element Method (FEM) and Finite Volume Method (FVM) to analyze the fluid flow in cylindrical piston distributing valves. Some of those who used FEM are: