Experimental and Numerical Analysis of forces on a Hydraulic Distributor

The paper relates about experiments and Computational Fluid Dynamics (CFD) analysis on forces acting on a commercial 4/3 distributor. Experimental results are reported, together with a detailed discussion to asses their reliability. The same results are then used to drive the approach to numerical simulation, in order to minimise the number of runs needed to gather the required informations in term of pressure drop and spool forces. A description of the benefits achievable with an extensive use of dimensional analysis is presented, showing how, within the validity limits of the same set of equations (turbulent or laminar), non-dimensional results of a numerical computation can be consistently extended to various flow conditions. Some final considerations are then reserved to a few indications useful for valve geometry improvement; furthermore a discussion is reported about some controversial numerical and experimental results.