CFD Simulation In Flow Field Of High Water Based Electromagnetic Pilot Valve With The Spherical Surface Seals

The electromagnetic pilot valve is the basic component in the hydraulic transmission and control, whose characteristics of the inner flow field directly influents the valve's performance, especially the moving valve cone. Applying FLUENT software of Computational Fluid Dynamics, the flow field of electromagnetic pilot valve is simulated and analyzed in the paper.According to actual structure and parameters, the 2D and 3D geometrical model of pilot valve is built by applying AutoCAD software. The model is transformed and imported into GAMBIT software, which is the preprocessor of FLUENT to generate mesh. Both the two and three-dimension flow field of valve are simulated in FLUENT.With the same opening and different pressure difference and same pressure difference and different opening the flow flied is simulated, influencing factors which influenced the pressure distribution and velocity distribution are founded. When sectional area sudden changed, mainstream is separated from wall, the eddy current area is generated in these places .After the steady state again simulating is carried out again by changing the boundary, found that the bottom intensity of pressure is defeated and cavitation modulus is -0.288 getting along with the intensity of pressure is lowest in orificing to melt out, may possibly produce the gas cave in process opening and being closed down in spool. Following adopt the cavitation model to be in progress simulating, the volume fraction getting vaporization water is 0.495, produces the gas cave indeed. The behaviour and efficiency is effected by the pilot valve the gas cave and eddy, so carry out appropriate improvement on the valve runner by changing transformed into transition level and smooth since the gentle cave of whirlpool has appeared and the quantity and intensity discovering a whirlpool by simulating reduce without exception obviously. Enhancing area of orificing mouth by diminishing the spool diameter can minimum intensity of pressure value enhances and cavitation modulus. Choosing right size of hermetic sealing steel ball also can make minimum intensity of pressure value enhance and the cavitation modulus to 0.45, after multigroup simulates, when the diameter sealing off steel ball is 0.5mm is best. Negative pressure area that enhances if adopt a diminution to reduce the gas cave coming spool diameter , the method of changing the sealing off the steel ball diameter is more effecter. Optimized designs reference basis is provided by comparing plain model and improved model.Process has been hit by a spool in motion with the pace is 0.01 m/s, has got spool pressure and velocity vector in the process closing in opening a sum respectively. The spool flows in the process of closure is more complicated than the liquid flow in the opening process and static state, so the quantity and intensity of eddy are all bigger. Because of the whirlpool, speed all has a component right away on each direction, therefore negative value has appeared.The total force and the static fluid force are carried on the theoretical analysis and the computation, the simulation result and the theory result are compared, has confirmed the simulation result accuracy. Radial force of the valve core is the analog computation and compared with the theory value, discovered could not have the card tight phenomenon. Carries on the research work has provided the basis for later to the valve design and the performance optimization.