0
Research Papers: Gas Turbines: Structures and Dynamics

Hole-Pattern and Honeycomb Seal Rotordynamic Forces: Validation of CFD-Based Prediction Techniques

[+] Author and Article Information
Kenny Krogh Nielsen

e-mail: kenny.krogh-nielsen@lr-ods.com

Kasper Jønck

Lloyd's Register ODS,
2900 Hellerup, Denmark

Harald Underbakke

Statoil,
NO-4035 Stavanger, Norway
e-mail: hun@statoil.com

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received June 27, 2012; final manuscript received July 6, 2012; published online October 11, 2012. Editor: Dilip R. Ballal.

J. Eng. Gas Turbines Power 134(12), 122505 (Oct 11, 2012) (10 pages) doi:10.1115/1.4007344 History: Received June 27, 2012; Revised July 06, 2012

This paper deals with modeling of hole-pattern and honeycomb seals. These are frequently used as balance piston seals in high pressure centrifugal compressor applications as they have the potential to facilitate superior rotordynamic damping characteristics while providing good leakage control. On the other hand it is also well-established that the rotordynamic performance of hole-pattern and honeycomb seals is very sensitive to convergence and divergence in the streamwise direction. The Isotseal bulk-flow code has shown difficulties in predicting the rotordynamic coefficients for convergent seal geometries or in cases with negative preswirl. This has led to increased interest in CFD-based analysis of seal dynamics. CFD-based models generally have less assumptions and are applicable for complex geometries or operating ranges not covered by bulk-flow codes. The CFD-based Instationary Perturbation Model (IPM) is utilized for the analysis of the hole-pattern and honeycomb seals. The rotordynamic forces are obtained by means of a time-dependent perturbation of the rotor position with respect to the stator. A sequence of perturbation frequencies is utilized to obtain the frequency dependence of the rotordynamic seal force coefficients. A strong effort has been put into validating the CFD-based perturbation modeling techniques against published experimental seal test data and the paper describes selected validation cases. A constant-clearance hole-pattern seal and a convergent honeycomb seal are analyzed and the results are compared to experimental results. The frequency dependence of the rotordynamic stiffness and damping characteristics of the seals is very well-captured for both types of seals.Finally, the IPM method was applied to a convergent hole-pattern seal to investigate the effects of eccentricity on the rotordynamic coefficients. The results are consistent with available experimental data.

Copyright © 2012 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Shaking motion of rotor in IPM analysis

Grahic Jump Location
Fig. 4

Hole-pattern: reaction forces at 200 Hz

Grahic Jump Location
Fig. 5

Hole-pattern: forces versus number of nodes

Grahic Jump Location
Fig. 6

Hole-pattern: direct stiffness

Grahic Jump Location
Fig. 7

Hole-pattern: cross-coupled stiffness

Grahic Jump Location
Fig. 8

Hole-pattern: direct damping

Grahic Jump Location
Fig. 9

Hole-pattern: cross-coupled damping

Grahic Jump Location
Fig. 10

Hole-pattern: effective stiffness

Grahic Jump Location
Fig. 11

Hole-pattern: effective damping

Grahic Jump Location
Fig. 12

Honeycomb: direct stiffness

Grahic Jump Location
Fig. 13

Honeycomb: cross-coupled stiffness

Grahic Jump Location
Fig. 14

Honeycomb: direct damping

Grahic Jump Location
Fig. 15

Honeycomb: cross-coupled damping

Grahic Jump Location
Fig. 16

Honeycomb: effective stiffness

Grahic Jump Location
Fig. 17

Honeycomb: effective damping

Grahic Jump Location
Fig. 18

ECC. Hole-pattern: direct stiffness.

Grahic Jump Location
Fig. 19

ECC. Hole-pattern: cross-coupled stiffness.

Grahic Jump Location
Fig. 20

ECC. Hole-pattern: direct damping.

Grahic Jump Location
Fig. 21

ECC. Hole-pattern: cross-coupled damping.

Grahic Jump Location
Fig. 22

ECC. Hole-pattern: effective stiffness.

Grahic Jump Location
Fig. 23

ECC. Hole-pattern: effective damping.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In