CFD analysis of compensator for meter out sensing system

The Meter Out Sensing (abbreviated to MOS) system is a new hydraulic architecture for multi actuators systems based on meter out control and featuring regeneration. The main benefits of the system are the energy saving obtained by regeneration and the simplicity of operation for the absence of electronic controls and sensors. The regeneration and compensation are obtained through a new component called Three Way Compensator. This component compensates the pressure drop across the meter out edge of the hydraulic block, thus the flow rate is independent of the load. Moreover, regeneration is automatically enabled under proper operating conditions. The paper deals with the Computational Fluid Dynamic analysis for studying the control characteristics of the prototype of three way compensator. Since the system is fully hydraulic, the condition for regeneration depends from the load conditions primarily, but also from the pressure drops across the components generated by the fluid flow. Thus the amount of regeneration flow in a working cycle not only depends on the load but also on the flow rate. Moreover, the compensator, like all hydraulic valves, is affected by flow forces phenomenon. This can deviate the control characteristics from the expected behavior in particular by changing the force balance on the valve, thus its position. The knowledge of flow resistance characteristics and flow forces are crucial to understanding the control characteristics and the energy behavior of this new system. The results will enhance the design and will stimulate the further optimization this critical component. The numerical method is validated by comparison with experimental results obtained on the test bench.