The thermal-mechanical deformations of CO₂ mixture gases dry gas seal based on two-way thermal-fluid-solid coupling model

Purpose This study aims to investigate the influence mechanism of thermal-mechanical deformations on the CO 2 mixture gases dry gas seal (DGS) flow field and compare the deformation characteristics and sealing performance between two-way and one-way thermal-fluid-solid coupling models. Design/methodology/approach The authors established a two-way thermal-fluid-solid coupling model by using gas film thickness as the transfer parameter between the fluid and solid domain, and the model was solved using the finite difference method and finite element method. The thermal-mechanical deformations of the sealing rings, the influence of face deformation on the flow field and sealing performance were obtained. Findings Thermal-mechanical deformations cause a convergent gap between the two sealing end faces, resulting in an increase in the gas film thickness, but a decrease in the gas film temperature and sealing ring temperature. The axial relative deformations of rotating and stationary ring end faces caused by mechanical and thermal loads in the two-way coupling model are less than those in the one-way coupling (OWC) model, and the gas film thickness and leakage rate are larger than those in the OWC model, whereas the gas film stiffness is the opposite. Originality/value This paper provides a theoretical support and reference for the operational stability and structural optimization design of CO 2 mixture gases DGS under high-pressure and high-speed operation conditions.