Session: 27-06 Lateral-Torsional, Cracked, and Bent Rotordynamics

Paper Number: 103162

103162 - Mitigation of Startup Coupled Lateral-Torsional Vibration of a Synchronous Motor Driven Integrally Geared Centrifugal Compressor 

This paper presents a study on the enhancement of the coupled lateral-torsional rotordynamic performance of a synchronous motor driven main air compressor. This is a four-stage integrally geared centrifugal compressor with two pinions. A compressor test showed that the low speed pinion experienced excessive lateral vibration during start. The pinion was excited when the motor speed passed through the first torsional natural frequency of the compressor drive train. A coupled lateral-torsional vibration analysis is then performed to predict the oscillating torques in different shafts, gear mesh forces and lateral vibrations of the pinions. To understand the mechanisms for the high pinion vibration, several factors affecting the pinion vibration, including the coupling torsional stiffness, the pinion bearing design and the impeller mass properties, are evaluated. The results show that the pinion startup vibration is sensitive to these design variables. A more flexible coupling can reduce the coupling oscillating torque and so the gearmesh forces. Tighter bearing clearance, larger preload factor and lighter impellers can increase the first two damping mode frequencies and damping ratios. Especially, the first backward mode plays more important role in the mitigation of the pinion vibration. To effectively mitigate this coupled vibration, some rotordynamic design considerations are also discussed in this paper.

Presenting Author: Zhusan Luo Linde, Inc.

Presenting Author Biography: Zhusan Luo is a Lead Rotordynamics Engineer of Turbomachinery Department, Linde Inc. in Tonawanda, New York. He takes charge of the rotordynamic design, analysis and testing of Linde turbomachinery. Dr. Luo is also responsible for bearing design, FEA, stress analysis, fatigue life prediction, vibration analysis, testing and diagnosis. Prior to joining Praxair, he worked with Siemens Industrial Turbomachinery Ltd., Lincoln, UK as a Principal Engineer and a Lead Rotordynamics Engineer. He started his engineering career as a faculty member of Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing, China and held positions of Lecturer, Associate Professor and the Head of Mechanical Design Section. He received his B.E. (1982) and M.A.Sc. (1985) in Mechanical Engineering from NUAA and Ph.D. (2001) in Applied Mechanics from the University of British Columbia, Vancouver, Canada. Dr. Luo is a member of the ASME, the Vibration Institute, and the IMechE (UK) and a Chartered Professional Engineer (CEng) registered in UK Engineering Council.

Authors:

Zhusan Luo Linde, Inc.
Carl L. Schwarz Linde, Inc.