Analysis of Flow Angles and Flow Velocities in Spool Valves for the Calculation of Steady-State Flow Forces

Abstract

A detailed analysis of the flow inside valves has become necessary for the optimisation of their static and dynamic performance. For this purpose, the contours of control edges as well as the shapes of sleeves, respectively of valve blocks, can be modified, resulting in different flow patterns. In addition, the flow velocities and flow angles on defined areas inside valves are needed for an estimation of physical quantities such as flow rates, flow forces, etc. Within this paper, measurements and CFD-simulations of a 2/2-way spool type test valve are analysed regarding flow angles and flow velocities including their distribution on the inlet and outlet areas. Different spool edge geometries are investigated in both flow directions. Furthermore, the impact of a chamfer and a fillet on a spool edge, on the flow angles and the flow velocities are analysed. The analysis results show that the shape of a spool edge influences the flow angles and the flow velocities. Both flow variables are significantly affected by the direction of the fluid flow through the valve. Moreover, considering the same inlet area, an increasing chamfer width, respectively an increasing fillet radius, results both in lower inlet and outlet flow angles.