Hydrodynamic Performance of Liquid Film Seals with Non-Newtonian and Thermal Fluid Lubrication

This study investigates the non-Newtonian effects on liquid film seal performance by considering cavitation and thermoelastic deformation—critical factors in high-pressure sealing applications such as nuclear reactor coolant pumps and aerospace systems. We developed a coupled numerical model that simultaneously solves the Reynolds equation using a power-law constitutive model to analyze hydrodynamic performance and employs the energy equation and thermal-structural analysis to determine the temperature distribution and radial taper deformation of the seal rings. The results reveal that the power-law exponent (n) critically influences sealing behavior: shear-thinning fluids (n < 1) reduce the load capacity by 12.7% due to expanded cavitation zones, whereas shear-thickening fluids (n > 1) increase the friction torque by 18.3% through thermally-induced tapered convergence effects. We established quantitative relationships between rheological properties, thermal deformation, and sealing performance, demonstrating that non-Newtonian characteristics fundamentally alter the fluid–structure interaction mechanisms in liquid-film seals. These findings provide a theoretical foundation for optimizing seal designs under extreme operating conditions where conventional Newtonian assumptions prove inadequate, particularly addressing the critical need for enhanced reliability in nuclear and aerospace sealing systems.