CFD Simulation Of The Flow Field In Safety Valve With High Water

The safety valve is the important component in the hydraulic transmission and control system, which maintenance the hydraulic system, 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 the safety valve is simulated and analyzed in the paper.According to actual structure and parameters, the 2D and 3D geometrical model of safety valve is built by applying AutoCAD and UG soft wares. 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 the valve are simulated in FLUENT.With the same opening and different boundary condition and the same boundary condition 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, the phenomenon of back flow wills appearing, 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 to -0.92MPa and cavitations modulus is -0.028, getting along with the intensity of pressure is lowest in orifice to melt out, may possibly produce the gas cave in process opening and being closed down in spool. Following adopt the cavitations model to be in progress simulating, the volume fraction getting vaporization water is 0.892, produces the gas cave indeed. The behavior and efficiency is affected by the safety 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. At the same time, by reducing the inlet pressure can minimum intensity of pressure value enhances and cavitations modulus. Optimized designs reference basis is provided by comparing plain model and improved model.When the valve's pace is 0.001 m/s, it has been got the spool pressure and velocity vector in the moving process. 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.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, gained that when the opening fixed, the total force and the static fluid force are increase with the pressure increasing, and when the pressure fixed, the total force and the static fluid force are reduced with the opening increasing. Carries on the research work has provided the basis for later to the valve design and the performance optimization.