Identification of Rotordynamic Forces in a Flexible Rotor System Using Magnetic Bearings Conference Paper uri icon


  • A method is presented for parameter identification of an annular gas seal on a flexible-rotor test rig. Dynamic loads are applied by magnetic bearings (MBs) that support the rotor. MB forces are measured using fiber-optic strain gauges (FOSGs) that are bonded to the poles of the MBs. In addition to force and position measurements, a finite element rotor model is required for the identification algorithm. The FE rotor model matches free-free characteristics of the test rotor. The addition of smooth air seals to the system introduces stiffness and damping terms for identification that are representative of reaction forces in turbomachines. Tests are performed to experimentally determine seal stiffness and damping coefficients for different running speeds and preswirl conditions. Stiffness and damping coefficients are determined using a frequency domain identification method. This method uses an iterative approach to minimize error between theoretical and experimental transfer functions. Test results produce seal coefficients with low uncertainties.

name of conference

  • Volume 5: Turbo Expo 2007

published proceedings

  • Volume 5: Turbo Expo 2007

author list (cited authors)

  • Zutavern, Z. S., & Childs, D. W.

citation count

  • 5

complete list of authors

  • Zutavern, Zachary S||Childs, Dara W

publication date

  • January 2007