0
RESEARCH PAPERS

Experimental Results From Controlled Blade Tip/Shroud Rubs at Engine Speed

[+] Author and Article Information
Corso Padova

Gas Turbine Laboratory, Ohio State University, 2300 West Case Rd., Columbus, OH 43234padova.1@osu.edu

Jeffery Barton, Michael G. Dunn

Gas Turbine Laboratory, Ohio State University, 2300 West Case Rd., Columbus, OH 43234

Steve Manwaring

 GE Aircraft Engines, Cincinnati, OH 45215

J. Turbomach 129(4), 713-723 (Aug 11, 2006) (11 pages) doi:10.1115/1.2720869 History: Received July 31, 2006; Revised August 11, 2006

Experimental results obtained for an Inconel® compressor blade rubbing a steel casing at engine speed are described. Load cell, strain gauge, and accelerometer measurements are discussed and then applied to analyze the metal-on-metal interaction resulting from sudden incursions of varying severity, defined by incursion depths ranging from 13μm to 762μm (0.0005in. to 0.030in.). The results presented describe the transient dynamics of rotor and casing vibro-impact response at engine operational speed similar to those experienced in flight. Force components at the blade tip in axial and circumferential directions for a rub of moderate incursion depth (140μm) are compared to those for a severe rub (406μm). Similar general trends of variation during the metal-to-metal contact are observed. However, in the nearly threefold higher incursion the maximum incurred circumferential load increases significantly, while the maximum incurred axial load increases much less, demonstrating the non-linear nature of the rub phenomena. Concurrently, the stress magnification on the rubbing blade at root mid-chord, at tip leading edge, and at tip trailing edge is discussed. The results point to the possibility of failure occurring first at the airfoil trailing edge. Such a failure was in fact observed in the most severe rub obtained to date in the laboratory, consistent with field observations. Computational models to analyze the non-linear dynamic response of a rotating beam with periodic pulse loading at the free-end are currently under development and are noted.

Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 17

(a) Axial component of tip force on airfoil in experiment no. 30. Incursion: ε=406μm(0.0160in.). (b) Circumferential component of tip force in experiment no. 30. Incursion: ε=406μm(0.0160in.).

Grahic Jump Location
Figure 18

Percent deviation of mid-chord root stresses on airfoil at selected frequencies

Grahic Jump Location
Figure 19

(a) Percent deviation of LE tip stresses on airfoil at selected frequencies. (b) Percent deviation of TE tip stresses on airfoil at selected frequencies.

Grahic Jump Location
Figure 8

Strain gauge measurements for rub-set and post-rub damping time scales. Incursion: ε=89μm(0.0035in.).

Grahic Jump Location
Figure 9

Center load cell measurement for rub-set time scale. Incursion: ε=89μm(0.0035in.).

Grahic Jump Location
Figure 10

Strain gauge measurements for shoe-sweep time scale. Incursion: ε=140μm(0.0055in.).

Grahic Jump Location
Figure 11

Load cells measurements for shoe-sweep time scale (first rub: top; third rub: bottom). Incursion: ε=89μm(0.0035in.).

Grahic Jump Location
Figure 12

Blade and casing after very light rub

Grahic Jump Location
Figure 1

Incursion mechanism photo

Grahic Jump Location
Figure 3

Load measuring unit (LMU)

Grahic Jump Location
Figure 4

Casing motion and incursion region

Grahic Jump Location
Figure 5

Typical load cell measurements

Grahic Jump Location
Figure 6

Typical strain gauge measurements

Grahic Jump Location
Figure 7

Time-scales of blade rubs

Grahic Jump Location
Figure 13

Closeup of blade trailing edge and casing after several moderately light rub experiments

Grahic Jump Location
Figure 14

Casing after rub of experiment no. 30. Incursion: ε=406μm(0.0160in.).

Grahic Jump Location
Figure 15

(a) Closeup of blade after experiment No. 31. Impact incursion at ε=762μm(0.0300in.). (b) Casing after rub of experiment No. 31. Impact incursion at ε=762μm(0.0300in.).

Grahic Jump Location
Figure 16

(a) Axial component of tip force on airfoil in experiment no. 26. Incursion: ε=140μm(0.0055in.). (b) Circumferential component of tip force in experiment no. 26. Incursion: ε=140μm(0.0055in.).

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.

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