CFD Analysis Of Fluid Flow Inside The Spool Valve At Unsteady Modes

The harmonic linearization method (dithering) is widely used in hydraulic servo systems; however, generated longitudinal oscillations of the spool result in unsteady hydrodynamic processes in spool valve throttle gap and change the structure of the flow that influences metering characteristics. The article deals with study of throttle gap flow structure in non-stationary conditions. The study was conducted by using a two-dimensional CFD model based on dynamic meshes in the ANSYS Fluent software package at various values of the spool valve oscillation frequencies. CFD model was successfully validated against experimental data from the literature. The results of numerical study of flow structure and flow parameters (such as the coefficient of jet contraction, the pressure diagram along a flow line) in the throttle gap are presented. The frequency dependence of the phase shift magnitude of volumetric flow rate oscillation relative to the harmonic valve oscillation is determined. Obtained model can be used for development of the refined one-dimensional mathematical model and simulation model of specified type devices