先导方式对比例阀振荡特性的影响机理OA北大核心

Different pilot control strategies for proportional valves induce varying extents of cavitation and vortex phenomena within the main valve control cavity,culminating in distinct oscillatory behaviors of the main spool.This study integrates CFD flow field simulations with visualization experiments to explore the flow characteristics of the control cavity when employing either a high-speed on-off valve bridge or a proportional pressure-reducing valve as the pilot stage.The influence mechanism of the pilot approach on main valve oscillations is elucidated by analyzing the flow field characteristics and vortex structures.A method to optimize the control cavity flow field is proposed,namely,chamfering the geometric corners and improving the wall smoothness.The results reveal that vortex generation and dissipation within the control cavity are intimately linked to spool oscillations.When the high-speed on-off valve bridge is utilized as the pilot,the flow field demonstrates significant fluctuations,intricate vortex structures,and periodic vortex variations,all contributing to pronounced main valve oscillations.Conversely,employing the proportional pressure-reducing valve as the pilot yields a more stable flow field,with uniform pressure distribution and simple vortices confined to geometric corners,where the interplay between pressure differentials and flow velocity further mitigates spool oscillations.This study offers a theoretical foundation for optimizing control cavity design and mitigating oscillations.