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Indexed by:Journal Papers

Date of Publication:2015-11-15

Journal:FINITE ELEMENTS IN ANALYSIS AND DESIGN

Included Journals:SCIE、EI、Scopus

Volume:106

Page Number:32-40

ISSN No.:0168-874X

Key Words:Centrifugal compressor; Geared rotor system; Changing load; Modeling; Vibration

Abstract:The variable critical speeds and resonances of a geared parallel-rotor system with five shafts effected by changing oil bearing stiffness due to different external loads are investigated in this paper. The rotor system of a modern centrifugal compressor is taken as the research object firstly. A finite element (FE) model of it is established by using rotating beam elements with 6 degrees-of-freedom (D0Fs), and linear mesh stiffnesses of the engaged helical gears are involved. The changing stiffness and damping of the oil bearings effected by different loads are calculated based on traditional oil-film fluid formula. Then, the Campbell diagrams of the whole rotor system under different loads on three output shafts are calculated based on the above model. Finally, comparing the obtained critical speeds, the load ranges are revealed to lead possible resonances of the rotor system near the operating speeds. (C) 2015 Elsevier B.V. All rights reserved