Attenuation of the Amplitude Vibration Level by Using Nonlinear Active Control Techniques Applied to a Hybrid Short Journal Bearing Using a Particular Rotor-Bearing System Configuration

Abstract

Inherent to turbomachinery are some common operational problems, such as the critical amplitude of motion that the machine may experience when passing through one or more of its natural frequencies. High range of vibration levels can be catastrophic to the equipment and its attenuation is needed to keep the system working healthily. To that end, the present work proposes the use of nonlinear active control techniques applied to a single hybrid short journal bearing using a particular rotor-bearing system configuration, which not require the assumption of an exact symmetry in the operation of the two journal bearings located at both ends of the rigid shaft such as the classical Jeffcott rotor model. The analysis is focused by reducing the amplitude shaft vibration of the rigid rotor crossing its first resonance. The oil injection port is modeled by mean of the Dirac Delta Function.