Estimation of Erosion Effects Due to Solid Contaminant in Hydraulic Valves

Solid contaminant is one of the major causes of component failures and system brakedowns in fluid power systems, Mote-than 80% of severe damag'es can be referred back to the, effects of fluid contamination. The traditional approach to the solution ofthis Rroblem is the introduction of Rroger1x designed filtration elements combined with the development of filtration strategies tailored for every application need. This approach can be considered substantially passive in nature, since it' allows the contaminant to be present in the fluid and provides means for its removal in order to keep either distribution or density of' solid- particles within prescribed limits. The passive approach, however, does t:J,0t anow any dYhamic estimation of the damages caused to components by fluid contamination, and the knowledge. gained on the ,oorrelation of fluid contamination to component damage is mainly empirical in nature. The work presented in the paper is part of a comprehensive activity aimed' at correlating· solid parth;le erosion effects. to hydraulic' fluid (usually mineral oil) contamination level, as defined by existing (ISO and NAS) standards. The tool used to predict solid particles erosion is a cornputational11uid dynamics (CFD) solution (obtained using a commercialcode) of the' flow field inside a hydraulic valve, coupled with lagrarrgian equation of motion solutio)) for solid particles subject to viscous forces.