Deformation Simulation Analysis of Mechanical Seal with Superconducting Magnetic Assistance Under Multi-Field Coupling and Its Influence on Lubrication Performance

This study investigates the influence of thermoelastic deformation on the lubrication performance of a superconducting magnetically assisted turbopump mechanical seal, with particular emphasis on film thickness and leakage. A spiral-groove hydrodynamic lubrication model based on the Reynolds equation and film energy equation is used to calculate the liquid-film load capacity and leakage, while a superconducting magnetic-force model based on the Bean model and electromagnetic finite-element analysis is employed to determine the magnetic-force contribution. The calculated mechanical loads and thermal boundary conditions are subsequently introduced into a thermoelastic finite-element model to obtain the deformation of the rotating and stationary seal rings. The results show that increasing the sealing clearance causes both the superconducting magnetic force and hydrodynamic liquid-film force to decrease nonlinearly. At a fixed clearance, the magnetic force is nearly independent of rotational speed, whereas the liquid-film force increases with increasing speed. The rotating ring exhibits greater deformation than the stationary ring, resulting in a non-parallel, approximately conical seal face. The deformation-induced change in the seal-face geometry is incorporated into the film-thickness model using the minimum and maximum film thicknesses, hmin and hmax. The results show that considering seal-face deformation leads to a smaller predicted minimum film thickness and a larger leakage rate than those obtained from the undeformed model. These findings indicate that thermoelastic deformation should be considered in the lubrication-performance evaluation of superconducting magnetically assisted mechanical seals, particularly under low-speed operating conditions.