Study on Controllable Deformation of the End Faces of Mechanical Seal Based on Piezoelectric Ceramics

A controllable mechanical seal structure based on piezoelectric ceramics is proposed to address the uncontrollable problem of liquid film instability during the operation of a mechanical seal. The mechanical seal adapts to variations in operating conditions and maintains a stable operating state by adjusting the end-face gap distribution of the seals. Firstly, the piezoelectric-mechanical multiphysics coupling model is established based on finite element software. The deformation law of the stator end face caused by voltage and the circumferential quantity of piezoelectric ceramics is analyzed. Then, a test device is developed to measure the end-face deformation of the stator. The deformation law of the stator end face is analyzed. Finally, based on the multiphysics coupling analysis model, the performance controllability of the mechanical seal under various sealing conditions is examined. The results show that the end face of the stator produces radial taper and circumferential waviness and that the deformation of the stator increases with increasing voltage, which facilitates the rapid formation of a convergent cone between the seal end faces. This enhances the hydrodynamic and hydrostatic effects of the fluid film and improves its load-bearing capacity. Increasing the number of piezoelectric ceramics on the back of the stator reduces circumferential waviness deformation and increases radial taper deformation, causing the end-face deformation of the stator to become more circumferentially uniform. This reduces the hydrodynamic effect and increases the hydrostatic impact of the fluid film, which enhances the stability of seal operation. The multiphysics coupling analysis results indicated that increasing the voltage of the piezoelectric ceramic enables the mechanical seal to transition from a contacting state to a non-contacting state. This reduces seal face wear and temperature rise while increasing the leakage rate. The results provide theoretical guidance for the design of controllable mechanical seals.