Impact of Frequency Dependence of Gas Labyrinth Seal Rotordynamic Coefficients on Centrifugal Compressor Stability Conference Paper uri icon


  • A numerical model developed by Thorat & Childs [1] has indicated that the conventional frequency independent model for labyrinth seals is invalid for rotor surface velocities reaching a significant fraction of Mach 1. A theoretical one-control-volume (1CV) model based on a leakage equation that yields a reasonably good comparison with experimental results is considered in the present analysis. The numerical model yields frequency-dependent rotordynamic coefficients for the seal. Three real centrifugal compressors are analyzed to compare stability predictions with and without frequency-dependent labyrinth seal model. Three different compressor services are selected to have a comprehensive scenario in terms of pressure and molecular weight (MW). The molecular weight is very important for Mach number calculation and consequently for the frequency dependent nature of the coefficients. A hydrogen recycle application with MW around 8, a natural gas application with MW around 18, and finally a propane application with molecular weight around 44 are selected for this comparison. Useful indications on the applicability range of frequency dependent coefficients are given.

name of conference

  • Volume 6: Structures and Dynamics, Parts A and B

published proceedings

  • Volume 6: Structures and Dynamics, Parts A and B

author list (cited authors)

  • Vannini, G., Thorat, M. R., Childs, D. W., & Libraschi, M.

citation count

  • 5

complete list of authors

  • Vannini, Giuseppe||Thorat, Manish R||Childs, Dara W||Libraschi, Mirko

publication date

  • January 2010