Design and Development of Large Radial Clearance Magnetic Fluid Seal with DN 100000

Abstract

The magnetic fluid based rotary shaft seal is the most successful technological newlineapplication of magnetic fluids. This is because of its simple design and high sealing newlineperformance than the other conventional seals. The unique advantage of using the newlinemagnetic fluid seal is that it offers total hermetic sealing with high reliability and newlineminimum wear and tear. It also offers high speed sealing capabilities as well as newlinefacilitates the possibility of maximum torque transmission. These seals can be used newlinein a wide range of spectrum including from exclusion seal for bearings to the highpressure newlinedifferentials and high-speed sealing devices. The only challenge with the newlinemagnetic fluid rotary seal is to prevent the temperature rise due to the higher speed newlineor large shaft diameter. The temperature rise is due to the frictional power loss newlinebetween the sealing stages. One possibility to reduce the temperature rise is by newlinedesigning the seal with the large radial clearance (and#8805; 0.25 mm). Large radial newlineclearance design presents its own challenges as the magnetic field inside the radial newlinegap decreases which deteriorates the seal performance. To balance out this, newlineoptimization of the magnetic focusing structure is required. newlineIn the present thesis, the main objective of the work is to develop the large radial newlineclearance (and#8805; 0.3 mm) vacuum rotary seal for the DN = 100,000 using minimum newlinenumber of sealing stages. To understand the working of seal and the parameters newlineaffecting the seal performance, the static seal experiments were carried out. The newlineparameters affecting the sealing performance were evaluated using magnetic newlinefluids with different saturation magnetizations as well as different plug heights with newlinerespect to the pole-piece height. The experiments were simulated using the finite newlineelemental method-based software FEMM (Finite Elemental Method Magnetics) newlineand compared with the experimental results. Results shows that there is one newlineparticular optimum fluid height above which the pressure differential remains newlineconstant. Results also suggest that, as flui