Effect of generalized dimple shape on load-carrying capacity and leakage characteristics of laser surface textured dry gas seal

Abstract

Abstract A new formula is employed to describe the dimple boundaries by considering edge number, superellipse coefficient, long axis radius and inclined angle, which make it possible to describe the boundaries of more typical dimple patterns by a unifiend equation. A mathematical model for obtaining the pressure distribution of dry gas seal with polygon dimple surface is established. The influence of the key geometrical parameters of polygon dimple on opening force and leakage rate is studied. The optimized geometries of generalized polygon dimple for the maximum opening force are obtained. Results show that an inclined quadrilateral dimple with multi rows in the radial direction presents the largest opening force. The opening forces of the two-sided and quadrilateral dimples with micron-scale are significantly better than that of millimeter apertures, while the opening forces of the triangular, pentagonal and hexagonal dimples with millimeter-scale are larger than that of the micron types. The shape profile parameters, directional parameters and radial dimple number of polygon dimples should be properly designed for excellent LCC and leakage characteristics.