Research On The Rotating Phenomenon Of The Single Micron Solid Particle In Clearance Of Spool Valve

Relying on cylindrical sliding fit clearance which is only a few microns to tens of microns,hydraulic spool valve,plunger pump and hydraulic cylinder achieve the function of guidance and seal.When micron sensitive particles which have the same size as clearance invade the fit clearance,would cause the abrasion of locomotion joints and clamping.However,the clamping induced by solid particles is one of the most common faults of hydraulic system,which is the main reason for performance degradation and defunctionalization in fluid control of hydraulic components,which can also be the main source for stability,safety and reliability declined in hydraulic system.Therefore,it is of great significance for the design of clamping-free hydraulic components to reveal the clamping mechanism induced by solid particles on the micron level.Micron fit clearance of spool valve and contour of sensitive particles are simplified as 2-D model,the Arbitrary Lagrangian-Eulerian technique of solid-fluid coupling module in COMSOL software is used to conduct the simulation investigation of the movement characteristics of micron particles in clearance of spool valve in this paper.The results indicated that,following the oil flow,micro particles will rotate in the clearance and the trajectory of center will fluctuate up and down.Considering the nonideal actual morphology of spool valve's clearance,irregular shapes and rotating phenomenon of the actual sensitive particles,when the sensitive particles contact top and bottom surfaces of the clearance simultaneously,it would become the clamping factor to induce the spool valve's clamping.The main effect is the maximum radial displacement induced by the difference of particles and pressure grooves.In order to improve the reliability of this research,designed the visualization experimental scheme and device of the particles motion in the clearance of spool valve.The main contents of this paper are as follows:In the first chapter,the academic research background and significance of spool valve's clamping induced by the particles was presented.The harm spool valve's clamping to hydraulic system was introduced,also the clamping factors and the preventive measures to reduce it were sketched.The history and current progress on clamping phenomenon of hydraulic spool valve at home and abroad was reviewed.In the second chapter,the mechanism of spool valve's clamping induced by the particles was sketched.The important functions,modules and solving objects of COMSOL software were introduced briefly.The basic concept of solid-fluid coupling was reviewed.The three common description methods of solid-fluid coupling was briefly introduced.In the third chapter,micron fit clearance of spool valve and contour of single micron particle are simplified as 2-D model,the Arbitrary Lagrangian-Eulerian technique of solid-fluid coupling module in COMSOL software is used to conduct the simulation investigation of the movement characteristics of micron particles in clearance of spool valve and it is found that a rotating phenomenon of particles is taking place in clearance of spool valve,that would scientifically explain the mechanism of spool valve's clamping induced by the particles.In the fourth chapter,2-D coupling model of pressure groove and solid micron particles were built.The effects of the trajectories caused by the difference of particles and pressure groove's shape,size and amount were explored.In the fifth chapter,designed the visualization experimental scheme and device of the micron particles motion in the clearance of spool valve.