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Unbalance-induced rub between rotor and compliant-segmented stator

Behzad, M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jsv.2018.04.032
  3. Publisher: Academic Press , 2018
  4. Abstract:
  5. Today, turbomachinery designers are trying to attain zero clearances for optimizing performance and efficiency of machine by designing advanced compliant-segmented seals. This trend involves secondary issues such as rotor-to-stator contact interaction which is to be treated with more technical knowledge in rotordynamic design and condition monitoring programs. The aim of this paper is to gain insight into dynamic interaction between a flexible rotor and a set of compliant arc-shaped segments as stator system. Specifically, the unbalanced-induced forward rubbing response is investigated in tight clearance condition during resonance-passing situations. A Jeffcott rotor modeling is used for representing the flexible rotor. A set of linear elastically-mounted rigid bodies with arc-shaped inner surfaces, which are arranged circumferentially around the rotor, are assumed as the model of the stator. The effects of mass, rotary inertia, translational and tilting stiffnesses are taken into account in the segment modeling. To compute the contact dynamic response, the equations of motion are coupled via Lagrange multiplier technique. The constrained equation of motion is solved by an implicit predictor-corrector time-marching numerical algorithm. Investigations reveal that the steady-state coupled rubbing solutions exist for the rotor interacting with the segmented stator. The solutions are classified with respect to stator properties, e.g. the number of segments and the stator stiffness. The synchronous rubbing solution covers various feature including shift in resonance speed, lower amplitude of rotor's vibration, smooth rise and fall in case of soft segments, jump phenomena in case of stiff segments, chaotic orbiting motion under effects of segment mass, etc. as are discussed in detail. © 2018 Elsevier Ltd
  6. Keywords:
  7. Compliant seal ; Dynamic ; Rotor ; Rub ; Segment ; Stator ; Condition monitoring ; Dynamics ; Equations of motion ; Lagrange multipliers ; Rotors ; Stators ; Stiffness ; Dynamic interaction ; Equation of motion ; Jeffcott rotor model ; Numerical algorithms ; Optimizing performance ; Predictor corrector ; Tilting stiffness ; Rigid rotors
  8. Source: Journal of Sound and Vibration ; Volume 429 , 2018 , Pages 96-129 ; 0022460X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0022460X18302578