Theoretical analysis and experiment on gas film stiffness with slip flow in a spiral-grooved dry gas seal

Abstract

Purpose This study aims to study the gas film stiffness of the spiral groove dry gas seal. Design/methodology/approach The present study represents the first attempt to calculate gas film stiffness in consideration of the slipping effect by using the new test technology for dry gas seals. First, a theoretical model of modified generalized Reynolds equation is derived with slipping effect of a micro gap for spiral groove gas seal. Second, the test technology examines micro-scale gas film vibration and stationary ring vibration to determine gas film stiffness by establishing a dynamic test system. Findings An optimum value of the spiral angle and groove depth for improved gas film stiffness is clearly seen: the spiral angle is 1.34 rad (76.8º) and the groove depth is 1 × 10–5 m. Moreover, it can be observed that optimal structural parameters can obtain higher gas film stiffness in the experiment. The average error between experiment and theory is less than 20%. Originality/value The present study represents the first attempt to calculate gas film stiffness in consideration of the slipping effect by using the new test technology for dry gas seals.

Research Progress on the Dynamic Stability of Dry Gas Seals

“…Green [40] conducted real-time monitoring and control of the seal's dynamic behavior through experiments, and further explored the root cause of poor seal dynamic stability. Based on the Reynolds equation model, Lu et al [41] tested the stiffness of the gas film in a dry gas seal under the sliding effect using a new technology and found that the optimal spiral angle of the stiffness of the air-enhanced film was 76.8 • , the groove depth was 1 × 10 −5 m, and the average error of the experimental and theoretical calculations was <20%. He et al [42] conducted experimental research and verification on the gas film flow field at the end face of the dry gas seal under different working conditions and analyzed the influence of working condition fluctuations on the balance state of the gas film gap.…”

The effect of thermal-elastic deformation on the sealing performance of supercritical CO2 dry gas seal

“…Ma et al (2015Ma et al ( , 2016b obtained the working performance of DGS and studied the temperature and pressure distribution of the gas film, as well as its sealing performance. Xu et al (2020Xu et al ( , 2023 calculated the specific heat of CO 2 based on thermodynamic theory and explored the effect of gas film regulation on dry gas sealing performance. Zhang et al (2022) investigated the SCO 2 DGS at different inlet temperatures and believed that liquid CO 2 and two-phase CO 2 appeared on the sealing surface.…”

Effect of Laminar, Turbulent and Slip Conditions on the Dynamic Coefficients of a Dry Gas Seal

“…They showed that CFFGS has stable and good leakage performance [2]. Lu et al calculated the gas film stiffness of dry gas seal by considering the slip effect of fluid films and optimized the groove shape to improve the gas film stiffness [3]. Other researchers also investigated dry gas seals using the physical perturbation method which extracts dynamic coefficients [4,5].…”