Research on Sealing Performance of Mechanical Seal for Excitation of Rotating Shaft

In this study, liquid film perturbed pressure equation is derived firstly using a Taylor Series expanding pressure formula. By linear film assumption, the axial stiffness and damping coefficients of the mechanical seal are derived. Then kinematical equation of the rotating shaft-mechanical seal system is established. The research focus on solving response of the rotating shaft-mechanical seal system and leakage of the mechanical seal when the rotating shaft is under different frequencies excitatied or under frequency disturbed in different form excitatied in this paper. The analytical results show that response of the rotating shaft-mechanical seal system can finally be close to the stable state, when excitatied frequency of the rotating shaft is disturbed in different form. But for amplitude of the displace between the stationary ring, rotating ring and rotating shaft occurs mutation point at the time when the excitatied frequency is disturbed, meanwhile the excitatied frequency of the rotating shaft is disturbed in rectangular pulse form or in instant maximum pulse form. It will cause liquid film thickness to happen mutation until the leakage increases and mechanical seal fails at last. The study results show that the sealing performance of mechanical seal and excitatied frequency of the rotating shaft has closely positive correlation. The rotating shaft-mechanical seal system can be optimization design and performance prediction based on the study of this paper.