Regulation of frictional temperature rise of furan resin-impregnated graphite seal rings through circular dimple-type textures

Purpose The shaft-end mechanical seal system, consisting of a static impregnated graphite ring and a dynamic metal ring, is a critical component in the aerospace integrated drive generator. With the continuous upgrade of aircraft engines and the increase in rotational speed, the seal interfaces under harsh frictional conditions are encountering new application issues closely related to frictional heat. This study aims to regulate the frictional temperature rise of seal rings for engineering applications. Design/methodology/approach To alleviate the influence of frictional temperature rise on sealing reliability, circular dimple-type textures were fabricated on the surfaces of aero-generator graphite seal rings using a laser process. The influence of texture diameter dt, area density of textures γt and texture depth ht on the frictional performance of graphite seal rings was investigated using single-factor experiments on a face-to-face tribometer. Computational fluid dynamics simulations were conducted to investigate the frictional heat generation and hydrodynamic characteristics. Findings The surface-textured graphite seal ring with a texture diameter dt of 200 µm, a texture depth ht of 40 µm and an area density of texture γt of 10%, exhibited the best ability in regulating the friction-induced temperature rise. Compared to the untextured sample, the coefficient of friction decreased by 37.2% and the maximum temperature rise decreased by 42.0%. Originality/value Since adopting new impregnated graphite materials in aircraft is highly challenging, it is a novel and feasible approach to realize the regulation of frictional temperature rise of aero-generator graphite seal rings through circular dimple-type textures.