CFD analysis of pressure loss during flow by hydraulic directional control valve constructed from logic valves

The aim of this paper is to investigate the reduction of flow resistance in a hydraulic system. The undertaken matter is focused on a spool type directional control valve with pilot operated check valves. In the paper there is a proposition of replacing a 4-way directional control valve with pilot operated check valves by suitable unit consisting of logic valves. Therefore, a body of new directional control valve has been designed. Four logic valves are mounted on the body and closed with a cover on which electromagnetic pilot valve is assembled. The hydraulic ports of the body are in accordance with the standard ISO 4401 - 08-07-0-94, so the proposed new directional control valve can be applied alternatively to a directional spool valve. An important task given during the work is to create the systems of flow paths inside the body, which are assumed to be performed with simple technologies like: drilling, boring and milling. The system of the designed flow paths is verified by CFD analysis with the use of ANSYS/FLUENT program on three-dimensional model. Obtained results are compared with the results of the characteristics given in catalogues and coming from experimental research of the prototype. The difference in pressure loss during flow for the logic valve taken from CFD calculation and the catalogue do not exceed 5%. Presented in the paper directional control valve may operate for volumetric flow rate up to 450 dm(3)/min and the pressure up to 42 MPa. In the proposed solution, although simple technologies of making flow paths were applied, the pressure losses were reduced over 35%. The developed solution is close to a standard directional spool valve and can be assembled on an identical sub-plate. (C) 2012 Elsevier Ltd. All rights reserved.