Generation Mechanism of Flow Force Acting on Spool Valve

Abstract

In hydraulic systems, spool valves play an important role. When the spool moves to the left or right, the flow path in the control valve changes, and the flow rate of hydraulic oil is controlled by the valve opening. Since high-pressure fluid flows into the valve, it is necessary to predict the behavior of the spool with high accuracy. One of the problems that spool valves have the hydraulic vibration caused by the high-pressure fluid. There is a need for a control valve that can suppress the hydraulic vibration even if it is used stand-alone. The purpose of this study is to visualize the flow field in the spool valve using three-dimensional computational analysis, and to clarify the generation mechanism of the flow force acting on the spool. The flow force acting on the spool was caused by the pressure difference between the high-pressure region generated by the impact of the jet and the low-pressure region through which the high-speed jet passed. Fluctuation of the jet flow occurred when the valve opening became narrow. The unsteady fluctuation of the jet flow had a significant effect on the unsteady variation of the flow forces.