Dynamic stability of dry gas seal under gas film adaptive-adjustment

Nearly all perturbation-based dynamic analyses of dry gas seals (DGS) rely on the constant gas film thickness (CGFT) assumption, which completely ignores the inherent coupling between gas film thickness and seal parameters—termed gas film adaptive-adjustment (GFAA) mechanism. This fundamental flaw may cause persistent design errors and catastrophic failures in seal industrial applications. To address this critical limitation, an enhanced dynamic stability model incorporating the intrinsic GFAA mechanism is developed. This model corrects the advantageous tracking capability parameter intervals derived from conventional CGFT assumption, providing a more reliable basis for dynamic design, with its effectiveness validated against multiple experimental datasets. Additionally, a novel five-parameter dynamic tracking matching and optimization prediction model is established. The results demonstrate that the adaptive response of gas film to parameter variations dominates the actual tracking behavior of stator. As a result, the advantageous parameter intervals for dynamic tracking under GFAA mechanism are significantly narrower than those under CGFT assumption, with distinctly different tracking characteristics. Targeting optimal stator tracking, the proposed model realizes three-dimensional precise regulation of seal clearance by coupling structural parameters and gas film thickness. The core strategy is to reduce gas film thickness while maintaining stability via increased balance ratio, achieving a rare synergistic enhancement of all key DGS performance with a minimum prediction error of 1.37%. The optimized design reduces leakage rate and stabilization time by 70.43% and 71.4%, respectively, while increasing gas film force and comprehensive dynamic tracking coefficient by 13.25% and 4.46%. This approach demonstrates strong potential for high-performance gas face seal design and stability control.