Performance Study On End Face Mechanical Seal With Macro-Pores

Surface texture technology such as mirco-pores has been widely used in the mechanical seal end faces, but its dynamic pressure effect is low under the condition of the high pressure and large film thickness. The sealing performance of that operating conditions can not be effectively improved and limit its further application. In view of this phenomenon, this paper proposed a macro-porous hydrodynamic surface texture, by which the lubricant film is collected and guided and the dynamic pressure effect and the stability of the liquid film is significantly improved.Considering the fluid cavitation, a theoretical model of the macro-porous liquid hydrodynamic mechanical seal is established. The sealing working conditions and pore’s structure parameters on the performance of mechanical seal are analyzed. The mechanism of the macro-porous surface texture is disclosed and the pore structures are optimized. Considering the effect of sealing pressure on the face deformation and the coupling effect between the film pressure and the surface deformation, a fluid-solid coupling model of the macro-porous mechanical seal is established. The finite element method and the finite difference method are combined to solve the coupled model. The influence of operating parameters and geometric parameters on the end face deformation and the sealing performance are analyzed. Sealing performance test benchs are constructed, by which the friction and the seal performance test of the macro-porous with different configuration texture surfaces are carried out.The results are listed here.(1) Compared with the micro-porous end face mechanical seal, macro-porous end face seal is easier to produce the cavitation effect at the low speeds conditions, so it has better dynamic pressure characteristics than the former. The longer the aperture or half axial length is, the better the liquid film stability between the end faces is.(2) The diamonded-shape macro-pores have better liquid film stability, opening characteristic and lower leakage rate than the other holes. At the low speeds conditions, the end face seal with bidirectional and inclinational diamonded-shape macro-pores can open quickly. The face wear and the leakage rate can be greatly reduced during startup. The non-tilt diamond micro-pores show the best stability of the liquid film.(3) The face circumferential waviness deformation is determined by the pore’s structure and the rotation speed. The radial taper deformation of the seal face is determined by the seal ring macroscopic dimensions and the seal pressure. These two kind parameters on seal deformation have no effect on each other.(4) Experiment results show that:compared with the smaller pores, the end face seal with bidirectional and inclinational diamonded-shape macro-pores, when ξ is0.6-0.9and the diamonded-shape macro-pores of the bigger aperture can obtain the minimum friction coefficient, temperature and wear, and the macro-pores end face has the better dynamic pressure effect and wear-resisting performance is verified.The achievement in this paper perfect the design theory and method of the macro-pores end face seal. The problems of the weak dynamic pressure effect of micro-porous face seal and the poor film stability in a wide pressure range are resolved in the low speed devices, so it is quite practical.