Effect of seal clearance on leakage and dynamic characteristics of hole-pattern damping seals

Purpose The purpose of this study is to investigate the influence of sealing clearance on hole-pattern damping seals (HPDS) and smooth annular seals (SPS). Design/methodology/approach Using ANSYS CFX transient moving mesh and elliptical whirl models, this study comparatively analyzes both seals’ performance across varying clearances. The results were validated through experiments on a cylindrical seal test platform. Findings At clearances Cr = 0.2–0.5 mm, HPDS outperforms SPS in leakage control and rotordynamic characteristics. Leakage rises with the clearance for both seals, but the increase is more slowly for HPDS. Seal clearances increase, which decreases damping coefficients and increases stiffness coefficients for both seals. HPDS shows less reduction in damping and smaller changes in stiffness, leading to better clearance adaptability. However, SPS shows a significant damping drop despite its increased stiffness. Turbulent vortex compression inside HPDS cavities reduces the clearance permeable layer, hindering fluid flow leakage. Vortices in HPDS cavities form a spring-damper hybrid structure that absorbs shaft vibrations. Consequently, HPDS shows better dynamic performance adaptability within 0.2–0.5 mm clearances, although its effective damping coefficient decreases as the clearance size increases. Originality/value This article focuses on studying the leakage and dynamic characteristics of the sealing clearance’s adaptability of the HPDS. It also explains the internal mechanism that makes this seal more adaptable than the SPS within the clearance range of 0.2–0.5 mm.