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The effect of cavitation plays a fundamental role in the hydraulic components design and the capability of predicting its causes and characteristics is fundamental for the optimization of fluid systems. In this paper, a multidimensional CFD approach is used to analyze the cavitating phenomena typical of hydraulic components using water as operating fluid. An open source fluid-dynamics code is used and the original cavitation model (based on a barotropic equation of state and homogeneous equilibrium assumption) is extended in order to account also for gases dissolved in the liquid medium. The effect of air dissolution into liquid water is modeled by introducing the Henry law for the equilibrium condition, and the time dependence of solubility is calculated on a Bunsen Coefficient basis. Furthermore, a simplified approach to turbulence modeling for compressible flows is coupled to the cavitation model and implemented into the CFD code.

This paper studies the influence of the discharge chamber geometrical parameters on the steady-state characteristics behavior of a conical seat valve having compensating profile. More in details, starting from the analysis of the experimental behavior of an actual valve showing inefficient characteristic curves, the metering openings leading to the transition from under to over compensation are individuated. Then, a 3D CFD steady-state, incompressible and isothermal analysis is involved, mainly to evidence the valve discharge coefficient and flow-forces variations with operating conditions. After, two alternative valve configurations, presenting a low pressure region designed to optimize the flow-forces compensation, are characterized through the 3D CFD analysis.