Influence of width of squeeze film damper on the transient response of rotor systems

The squeeze film damper (SFD) is a damping device that has been widely used in rotating machines. The SFD can effectively suppress rotor vibration and reduce transmitted forces. However, it would cause complex motions of the rotor system under specific operating conditions. This paper investigates the support structure of a high-pressure stage simulated rotor in an aircraft engine. A dynamic model of the SFD considering the effects of inertia and cavitation is established to investigate the influence of structural parameters on the stiffness and damping coefficient of the damper. Subsequently, a finite element model of the Jeffcott rotor–SFD system is developed to explore the effects of the structure parameters of the SFD on the critical speed, mode shapes, and other dynamic characteristics of the Jeffcott rotor–SFD system. Experimental tests are conducted to validate and refine the numerical calculations regarding the dynamic characteristics of the rotor–damper system. The results indicate that there is consistency between numerical simulations and experimental results. Within a certain range, enlarging the width of the damper can significantly increase the magnitude of the pressure distribution of the oil film. However, when the pressure amplitude increases to the saturation vapor pressure of the lubricating oil, the cavitation effect begins to manifest. As the width of the damper increases, both the stiffness coefficient and damping coefficient of the SFD are enhanced. Consequently, the vibration reduction effectiveness of the SFD is significantly improved.