Dynamic Modeling and Analysis of a Mechanical Seal System Considering Shaft Stiffness

Abstract

In the petrochemical industry, mechanical seal systems used in centrifugal pumps often operate under medium-speed and light-load conditions. Component vibrations can cause dynamic variations in opening force and slight displacements, leading to failures such as seal face wear and leakage. This study considers the influence of shaft elasticity and introduces oil film stiffness parameters to establish a refined dynamic model of a coupled mechanical seal system comprising the rotating ring, stationary ring, and spindle. The model is used to analyze the variation patterns of axial displacement, radial displacement, and opening force of the components under different rotational speeds. The results show that the fluctuation frequency of the opening force is positively correlated with the rotational speed. An increase in speed intensifies the vibrational frequency of the axial displacement of the rotating ring, resulting in reduced stability. The axial displacement of the stationary ring exhibits good temporal dynamic stability. When the rotational speed reaches 1200 r/min, the vibration frequency of the shaft's radial displacement approaches the natural frequency of the shaft system, leading to seal face wear and failure.