Theoretical And Experimental Research On Magnetic Powder Rotary Seal

Magnetic powder seal has the characteristics of strong pressure resistance,high temperature resistance,low temperature resistance,simple and reliable structure,no pollution and so on.Magnetic powder seal is of great research value in solving the problem of yin-yang ball head of oscillating nozzle.In this thesis,the theory and pressure resistance strength of magnetic powder rotary seals are studied from theory,finite element analysis and experiment,which lays a foundation for solving the problem of magnetic powder seal.(1)Puts forward in the sum of the magnetic induction increment at the pole teeth is an important parameter to measure the pressure resistance strength in the magnetic powder seals.Researchs the continuity equation of porous media,mass conservation equation,and seepage control equation.Obtains computational formula of inertial resistance factor and viscous resistance factor in magnetic powder porous media.(2)Designs the magnetic powder plane sealing device,and uses the software of ANSYS to analyze the magnetic field.Designs multiple sets of experimental system for experiments.Obtains the leakage state of the sealed medium.Researchs the mechanism of magnetic powder seal,and sealing performance of magnetic powder sealing gas and sealing liquid.The experimental results show that magnetic powder seals at all levels play a sealing role simultaneously.(3)Designs the magnetic powder rotary sealing device,and uses the software of ANSYS to analyze the magnetic field,and obtains the rules: with the pole teeth width increasing,the pressure resistance strength increases in the first then decreases.With the sealing gap increasing,the pressure resistance strength decreases obviously.Obtains the pressure resistance strength of the pole boots and shafts with different materials.Uses the software of Fluent to analyze the magnetic field,and obtains the rules: with the poriness increasing,the leakage rate increasing.With the teeth width increasing,the leakage rate decreases obviously.With the sealing gap increasing,the leakage rate decreases obviously.Designs experiment to research the influence of different pole teeth widths on actual sealing performance,the results show that with the teeth width increasing,the leakage rate decreases obviously.Finally,determins the main parameters of the magnetic powder rotary seals by synthesizing the analysis results.(4)Designs magnetic powder rotary seal experimental system.Researchs the relationship between different initial pressure,different rotational speed and the leakage rate of gas and liquid.The experimental results show that with the same initial pressure in the sealed cavity,the leakage rate decreases in the first then increases with the increase of rotate speed.The sealing effect of rotary seal is better than static seal.when sealing gas,magnetic powder seal in 0-600 k Pa will not fail.When sealing liquid,part of the magnetic powder sealing ring fails when the pressure is 400 k Pa,but there is no instantaneous leakage of the sealed medium,and the leakage rate is still controllable.There are 80 figures,15 tables,65 references in this thesis.