Research Papers: Gas Turbines: Heat Transfer

Brush Seals Used in Steam Environments—Chronological Wear Development and the Impact of Different Seal Designs

[+] Author and Article Information
Markus Raben

Institute of Jet Propulsion and Turbomachinery,
TU Braunschweig,
Hermann-Blenk-Str. 37,
Braunschweig 38108, Germany
e-mail: m.raben@ifas.tu-bs.de

Jens Friedrichs

Institute of Jet Propulsion and Turbomachinery,
TU Braunschweig,
Hermann-Blenk-Str. 37,
Braunschweig 38108, Germany
e-mail: j.friedrichs@ifas.tu-bs.de

Thomas Helmis

Siemens AG,
Power and Gas Division,
Rheinstr. 100,
Mülheim an der Ruhr 45478, Germany
e-mail: thomas.helmis@siemens.com

Johan Flegler

Siemens AG,
Power and Gas Division,
Rheinstr. 100,
Mülheim an der Ruhr 45478, Germany
e-mail: johan.flegler@siemens.com

1Corresponding author.

Contributed by the Heat Transfer Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 15, 2015; final manuscript received August 30, 2015; published online October 27, 2015. Editor: David Wisler.

J. Eng. Gas Turbines Power 138(5), 051901 (Oct 27, 2015) (10 pages) Paper No: GTP-15-1318; doi: 10.1115/1.4031531 History: Received July 15, 2015; Revised August 30, 2015

During the last decades, turbo machine efficiency was considerably increased by using more efficient seals. Brush seals, as a compliant contacting filament seal, have become an attractive alternative to conventional labyrinth seals in the field of aircraft engines as well as in stationary gas and steam turbines. The aim of today's research related to brush seals is to understand the characteristics and their connections, in order to be able to make performance predictions, and to ensure the reliability over a defined operating period. The wear behavior is essentially influenced by frictional contacts at the seal-to-rotor interface during operation. For realistic investigations with representative circumferential velocities, the TU Braunschweig, Germany, operates a specially developed steam test rig which enables endurance investigations under varying operating steam conditions up to 50 bar and 450 °C. Wear measurements and the determination of seal performance characteristics, such as blow down and bristle stiffness, are enabled by an additional test facility, using pressurized cold air up to 8 bar as a working fluid. This work presents the chronological wear development on both rotor and seal sides in a steam test lasting 25 days or 11 days, respectively. Interruptions after stationary and transient intervals were made in order to investigate the degree of wear. Two different seal arrangements, a single tandem seal, and a two-stage single seal arrangement, using different seal elements were considered. Besides a continuous wear development, the results clearly show that the abrasive wear of the brush seal and rotor is mainly caused by transient test operations, particularly by enforced contacts during shaft excursions. Despite the increasing wear to the brushes, all seals have shown a functioning radial-adaptive behavior over the whole test duration with a sustained seal performance. Thereby, it could be shown that the two-stage arrangement displays a load shift during transients, leading to a balanced loading and unloading status for the two single brush seals. From load sharing, and in comparison with the wear data of the tandem seal arrangement, it can be derived that the two-stage seal is less prone to wear. However, the tandem seal arrangement, bearing the higher pressure difference within one configuration, shows a superior sealing performance under constant load, i.e., under stationary conditions.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.


Chupp, R. E. , Hendricks, R. C. , Lattime, S. B. , and Steinetz, B. M. , 2006, “ Sealing in Turbomachinery,” NASA Glenn Research Center; Cleveland, OH, Report No. NASA/TM-2006-214341.
Jahn, I. H. , 2013, “ Maximizing Contacting Filament Seal Performance Retention,” ASME Paper No. GT2013-94261.
Schwarz, H. , Friedrichs, J. , and Flegler, J. , 2012, “ Design Parameters of Brush Seals and Their Impact on Seal Performance,” ASME Paper No. GT2012-68956.
Crudgington, P. F. , and Bowsher, A. , 2002, “ Brush Seal Pack Hysteresis,” AIAA Paper No. 2002-3794.
Büscher, S. , 2010, “ Untersuchung von mehrstufigen Bürstendichtungen für Dampfturbinen,” Ph.D. thesis, TU Braunschweig, Institute of Jet Propulsion and Turbomachinery, Verlag und Bildarchiv W.H. Faragallah, Braunschweig, Germany.
Schwarz, H. , Friedrichs, J. , and Flegler, J. , 2014, “ Axial Inclination of the Bristle Pack, a New Design Parameter of Brush Seals for Improved Operational Behavior in Steam Turbines,” ASME Paper No. GT2014-26330.
Raben, M. , Schwarz, H. , and Friedrichs, J. , 2013, “ Operating Performance and Wear Investigations of Brush Seals for Steam Turbine Applications,” ASME Paper No. GT2013-95442.
Crudgington, P. F. , Bowsher, A. , Lloyd, D. , and Walia, J. , 2009, “ Bristle Angle Effects on Brush Seal Contact Pressures,” AIAA Paper No. 2009-5168.
Osterhage, T. , 2001, “ Leckagearme Hochdruckgasdichtung für Dampfturbinen,” Ph.D. thesis, TU Braunschweig, Druckerei und Buchbinderei Wolfram Schmidt, Braunschweig, Germany.
Schwarz, H. , Friedrichs, J. , Kosyna, G. , Flegler, J. , Cooper, P. , and Georgakis, C. , 2012, “ Hochleistungs-Bürstendichtungen für große Druckgefälle,” TU Braunschweig, Braunschweig, Germany, Technical Final Report No. FKZ: 0327716P.
Hendricks, R. C. , Griffin, T. A. , Kline, T. R. , Csavina, K. R. , Pancholi, A. , and Sood, D. , 1994, “ Relative Performance Comparison Between Baseline Labyrinth and Dual-Brush Compressor Discharge Seals in a T-700 Engine Test,” 39th International Gas Turbine and Aeroengine Congress and Exposition, The Hague, Netherlands, June 13–16, Report No. NASA-TM-106360.
O'Neill, A. T. , Hogg, S. I. , Withers, P. A. , Turner, M. T. , and Jones, T. V. , 1997, “ Multiple Brush Seals in Series,” ASME Paper No. 97-GT-194.
Crudgington, P. F. , 1998, “ Brush Seal Performance Evaluation,” AIAA Paper No. 98-3172.
Bidkar, R. A. , Demiroglu, M. , Zheng, X. , and Turnquist, N. , 2011, “ Stiffness Measurement for Pressure-Loaded Brush Seals,” ASME Paper No. GT2011-45399.
Berard, G. , and Short, J. , 1999, “ Influence of Design Features on Brush Seal Performance,” AIAA Paper No. 99-2685.
Braun, M. J. , Canacci, V. A. , and Hendricks, R. C. , 1992, “ Flow Visualization and Motion Analysis for a Series of Four Sequential Brush Seals,” J. Propulsion Power, 8(3), pp. 697–702. [CrossRef]


Grahic Jump Location
Fig. 1

Axial inclination (left) and lay angle (right) [6]

Grahic Jump Location
Fig. 2

Brush seal behavior for different axial inclinations [6]

Grahic Jump Location
Fig. 4

Brush seal configurations

Grahic Jump Location
Fig. 5

Single pressure differences (BST15a)

Grahic Jump Location
Fig. 6

Discharge coefficients (BST15a)

Grahic Jump Location
Fig. 7

Blow down (BST15a)

Grahic Jump Location
Fig. 8

Bristle pack stiffness (BST15a)

Grahic Jump Location
Fig. 9

Bristle pack width (BST15a)

Grahic Jump Location
Fig. 10

Oscillating bristle rows, seal DS1 (Δp = 5 bar)

Grahic Jump Location
Fig. 11

Inlet pressure variation—single pressure differences (BST16a)

Grahic Jump Location
Fig. 12

Inlet pressure variation—discharge coefficients (BST16a)

Grahic Jump Location
Fig. 13

Eccentricity variation—single pressure differences (BST16a)

Grahic Jump Location
Fig. 14

Eccentricity variation—discharge coefficients (BST16a)

Grahic Jump Location
Fig. 15

Cold clearances—chronological development

Grahic Jump Location
Fig. 16

Cold clearances—circumferential profile, seal DS1

Grahic Jump Location
Fig. 17

Cold clearances—circumferential profile, seal DS2

Grahic Jump Location
Fig. 18

Shaft wear—maximum profile depth



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