Numerical Analyses Of Gas Lubricated Laser Surface Textured Mechanical Seals

A mechanical seal with laser-textured faces (LST-MS) is an innovative sealing technology developed in last decade. With its outstanding sealing and lubricating performance, the working behavior of a LST-MS can be improved to a large extent. The sealing performance of a gas lubricated LST-MS (GL-LST-MS) is theoretically studied and numerically analyzed in this paper. Firstly, the geometrical, the physical and the performance parameters are summarized and generalized systematically, and simplified into six non-dimensional parameters for a stable GL-LST-MS. Secondly, mathematical and physical models of a stable GL-LST-MS with square dimples are established for the hydrostatic or the hydrodynamic case. Finite element method is used to solve the Reynolds equation, in which the iteration method and the discret Petrov-Galerkin method are used to obtain the values of the six performance parameters: opening force, the increment in opening force, gas film stiffness, leakage rate, the opening force to leakage ratio, and the stiffness to leakage ratio. The effects of area density of dimples, the radial texturing proportion, the circumferential texturing proportion, the dimensionless dimple depth, the nondimensional seal parameter and the sealing pressure, on opening performance, seal stability and sealing behavior of such a seal is thoroughly studied. Thirdly, the principle for optimization of the texturing parameters is put forward. The principle is to make opening force larger and leakage lower of a GL-LST-MS as much as possible while the stability of the seal should be high enough. According to the principle, gas film stiffness and the stiffness to leakage ratio are selected as the objective functions for the optimization of the texturing parameters. In the end, optimized parameters of such a seal under different working conditions are obtained by numerous calculations, and the optimization of such a seal is accomplished. The research results can be used as the theoretical and instructive foundations for the design, selection, manufacturing and usage of a GL-LST-MS.