Experimental Analysis of the Unbalance Impact on a Rotor Supported by Incorporating Elastic Support

In rotor systems, vibration is unavoidable. Significant vibration not only generates noise and diminishes machine performance, but also compromises the service life and reliability of the equipment, potentially leading to safety hazards. The causes of rotor vibration are diverse and complex. One of the primary reasons for rotor system vibration is unbalance. However, there is limited experimental research on the coupled effects of unbalance and inlet pressure of squeeze film damper (SFD) on the dynamic characteristics of rotor system. This paper investigates the impact of unbalance and inlet pressure on the dynamic characteristics of a rotor-SFD system, as well as their combined effects, through modal and transient dynamic experiments. The results indicate that as the unbalance magnitude increases, the critical speed of the rotor system significantly shifts higher. The speed through the critical speed slows down. The amplitude of acceleration vibration significantly rises, exacerbating system instability. When the unbalance is relatively small at low speeds, reducing the inlet pressure of the SFD within a certain range can decrease the vibration amplitude of the system and enhance its stability. However, in the circumstances of significant imbalance and high speeds, the suppressive impact of inlet pressure on rotor system vibrations is significantly weakened.