Predicting Hydraulic Valve Flow Forces Using CFD

Abstract

This paper presents a method of using Computational Fluid Dynamics (CFD) computer simulations for hydraulic oil flow inside hydraulic valves. The main objective is to study “flow forces” - the hydraulic forces induced by oil flow on the actuators of hydraulic valves, with the aim of minimizing their effects or use their effects towards improving valve performance. Integration of solved pressure distribution and velocity fields from CFD simulation solutions over related valve component surface areas is employed to obtain the desirable flow forces and viscous flow wall drag effect has also been included. Different valve metering geometry has been simulated using a commercially available CFD software program. The hydraulic oil flow inside valves is assumed steady-state and normally in a turbulent mode. The complete simulation procedure is presented from parametric geometry creation with a 3-D solid CAD through final post-processing of results. Simulation results of several hydraulic valve applications, both spool valves and poppet valves, are included. Tests have been performed to measure flow force and oil flow rates. CFD results are compared to experimental results, in some cases, with good correlation.