Simulation On Dynamic Characteristics And Flow Field Of Large Flow Electro-hydraulic Directional Valve

With the high production and efficiency of coal mining technology widelyapplication, the performance "speed" of the support played a significant role inthe performance of the fully mechanized mining. The current commonly usedgood performance of large flow electro-hydraulic directional valve’s ratedflow was400L/min. Fully mechanized coal mining required further enhanceand faster movement speed of the support. As a result, it needed increase therated flow, and it was more and more important to do research on the largeflow electro-hydraulic directional valve.With the research of the valve structure characteristics and analyze of theworking principle of commonly used imported electro-hydraulic directionalvalve, the article derived the mathematical model of electro-hydraulicdirectional valve by force analysis of key parts and designed a large flowelectro-hydraulic valve by calculation. It used Matlab software to dosimulation on the model and got the initial parameters of dynamic characteristics. It used AMESim dynamic system simulation software to studythe dynamic characteristic of the electro-hydraulic valve system and based onthe fluid dynamics analysis software Fluent for simulation of internal flowfield of the master valve of electro hydraulic reversing.In the AMESim platform, it established the directional valveelectro-hydraulic control system and analyses of the dynamic characteristicsand did research on spool displacement, spool cone angle, the mastervalve orifice diameter and the effect of the spring force on the performanceof directional valve system. The research results showed that the spool beganto move at0.13s,0.23s can achieve the valve port to open stability, the mastervalve performed well in the process of movement and outlet flow reached astable value for1013L/min.It used CFD computational fluid dynamics software Fluent to simulate thelarge flow electro-hydraulic directional valve internal flow field to get thecharacteristic curves. Through the analysis of simulation results on the oilinlet conditions of P-A and oil return conditions of A-T of two kinds ofsituations can be obtained, uniform distribution of pressure dropped and thereexisted no obvious vortex. On this basis, this paper further discussed thecharacteristics of flow field inside of the master control valve in differentopening degree, different inlet valve sleeve hole cone angle and different ringcavity diameter, the results showed that: With the increase of the degree ofopening, the maximum speed of regional area increased, speeding up the opening time of the master valve, which was conducive to theimprovement of hydraulic stents working speed; the area and intensity of thevortex region decreases with increasing the degree of opening, which will helpreduce the wear of the valve plug and impact. In the simulation analysis oflarge flow electro-hydraulic directional master valve at different cone angle,verified the phenomenon that inclined orifice was beneficial to reduce thevortex, providing the theory basis of the selection of cone angle. Inaddition, when increasing the ring cavity diameter, the loss of turbulent kineticenergy was reduced, the import and export pressure loss of the master valvedecrease, proving that increase the ring cavity diameter can effectivelyimprove the valve flow capacity.