Loading...

Non-stationary Vibration of a Rotor with Foil Gas Bearings Passing Through Critical Speeds

khaji, Zahra | 2017

823 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50226 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Mohammad Navazi, Hossein
  7. Abstract:
  8. The use of air bearings was began the last decade. Oil-free air bearing technology is implemented in rotating machines such as turbines, Micro gas turbines and turbocharged, this technology has improved the efficiency of rotating systems. In rotating machines, at high speeds, passing through the critical speed happens. As a result, the natural frequency of the system is crossing the critical speed, which causes system instability and lack of system amplitude control. Instability causes damage to the system. The aim of this thesis is to investigate the nonstationary vibrations of a flexible rotor with air bearings in the passing critical speeds. Behavior of air bearings is also considered to be non-linear behavior, after the equations and boundary conditions is derived, stiffness and damping of rotor and air bearing system are models, then response of system is determine with Numerical method and Harmonic balance method. The use of air bearing system cause decrease of maximum amplitude, increase critical speed, safety and stability of the system. In conclusion, non-stationary vibration of a rotor with air bearings passing through critical speeds will be explained
  9. Keywords:
  10. Air Bearing ; Harmonic Balance Method ; Flexible Rotor ; Jeffcott Rotor ; Passing Through the Critical Speed ; Non-Stationary Vibrations

 Digital Object List

 Bookmark

No TOC