In this study, to improve the accuracy of the brush seal heat transfer model, based on the finite volume method (FVM) coupled with the three-dimensional Reynold-averaged Naviers-Stokes equations (RANS) equations of the Local temperature non-equilibrium (LTNE) model, and a mathematical model of the heat transfer and leakage characteristics of the brush seal was established. The distribution of the pressure, flow and temperature fields of the brush seal are analyzed. User-defined function (UDF) programming was performed for the LTNE model. And the LTNE model is then compared with the local temperature equilibrium (LTE) model in terms of the factors influencing the heat transfer and leakage characteristics. The results show that the maximum brush filament temperature increases with an increases in the pressure ratio, interference, and speed for both models; the fluid flow rate increases with an increases in the pressure ratio, interference, and speed; and the leakage rate increases with an increases in the pressure ratio and decreases with an increases in interference and speed. The maximum temperature of the brush filament under the LTNE model was found to be higher than that under the LTE model, but the maximum temperature difference does not exceed 3.1%. Additionally, the fluid flow rate under the LTNE model was higher than that under the LTE model, and the flow rate difference does not exceed 3.4%. And the leakage rate under the LTNE model was lower than that under the LTE model, and the leakage rates differ by no more than 9.0%. Ultimately, numerical analysis of the brush seal under the LTNE model was found to be more effective and consistent with actual working conditions than alternative models.

Addressing the stability issues of gas film floating ring seals under high-temperature, high-pressure, and vibrational conditions, where conventional floating rings fall short, three novel microtexture configurations are proposed: convergent, stepped, and rectangular shallow grooves. Dynamic characteristic governing equations for microtextured floating ring seals were established based on the perturbation method. A comprehensive parametric study was performed for different microtextured seals, and the influence mechanisms of various microtextures on gas film pressure distribution, stiffness, and damping characteristics were systematically investigated, revealing the underlying principles affecting seal dynamics. The research indicates that microtextures on the inner circumference of the floating ring significantly optimize pressure distribution and its gradients by enhancing the gas dynamic pressure effect. Specifically, compared with the conventional structure, the convergent microstructure reduces the leakage rate by 8.98% and increases stiffness by 5.00 times by suppressing fluid flow through a gradually narrowing gap; the stepped microstructure utilizes flow separation to generate vortices, achieving a 7.23% reduction in leakage rate and a 3.67-fold increase in stiffness; the rectangular shallow groove creates localized high-pressure zones, resulting in a 15.12% decrease in leakage rate and a 6.18-fold improvement in stiffness. All three microtextures regulate vortex motion, optimize local pressure distribution, and enhance energy dissipation, thus improving gas film flow characteristics. The proposed microstructural floating-ring gas film model is well validated by experimental data, showing a maximum discrepancy of 17.03% in the leakage rate. Furthermore, the developed solution effectively suppresses gas film instability, leading to remarkable improvements in the steady-state performance and dynamic stability of the sealing system. This work thus provides a novel theoretical framework and paves a robust technical pathway for the design of high-performance seals in extreme operating conditions.