Research Papers

Impact Analysis of Pocket Damper Seal Geometry Variations on Leakage Performance and Rotordynamic Force Coefficients Using Computational Fluid Dynamics

[+] Author and Article Information
Clemens Griebel

Institute for Energy Systems,
Technical University of Munich,
Garching 85748, Germany
e-mail: clemens.griebel@tum.de

Manuscript received June 25, 2018; final manuscript received June 29, 2018; published online December 4, 2018. Editor: Jerzy T. Sawicki.

J. Eng. Gas Turbines Power 141(4), 041024 (Dec 04, 2018) (9 pages) Paper No: GTP-18-1340; doi: 10.1115/1.4040749 History: Received June 25, 2018; Revised June 29, 2018

In this paper, different notch and partition wall arrangements of a fully partitioned pocket damper seal (FPDS) are investigated using computational fluid dynamics (CFD). The CFD model is derived for a baseline FPDS design reflecting the full sealing configuration with a structured mesh. Steady-state simulations are performed for eccentric rotor position and different operational parameters. The results are validated using experimental cavity pressure measurements. In transient computations, rotor whirl is modeled as a circular motion around an initial eccentricity using a moving mesh technique. Different whirl frequencies are computed to account for the frequency-dependent behavior of damper seals. The stiffness and damping coefficients are evaluated from the impedances in the frequency domain using a fast Fourier transform. The validated model is then transferred to varying designs. In addition to the baseline design, six different notch arrangements with constant clearance ratio were modeled. Moreover, two partition wall design variations were studied based on manufacturability considerations. Predicted leakage as well as frequency-dependent stiffness and damping coefficients are presented and the impact of geometry variations on these parameters is discussed. The results suggest that a single centered notch is favorable and indicate considerably higher effective damping for a design with staggered partition walls. A rounded partition wall design with significantly eased manufacturing reveals good performance.

Copyright © 2019 by ASME
Your Session has timed out. Please sign back in to continue.


Childs, D. W. , and Vance, J. M. , 1997, “ Annular Gas Seals and Rotordynamics of Compressors and Turbines,” 26th Turbomachinery Symposium, College Station, TX, pp. 201–220. http://oaktrust.library.tamu.edu/handle/1969.1/163429
Thomas, H.-J. , 1956, “ Instabile Eigenschwingungen Von Turbinenläufern, Angefacht Durch Die Spaltströmungen in Stopfbuchsen Und Beschauflungen,” AEG, Berlin, Technical Report No. 1150.
Lomakin, A. , 1958, “ Calculation of Critical Number of Revolutions and the Conditions Necessary for Dynamic Stability of Rotors in High-Pressure Hydraulic Machine When Taking Into Account Forces Originating in Sealings (in Russian),” Energomashinostroenie, 4(4), pp. 1–5.
Alford, J. , 1965, “ Protecting Turbomachinery From Self-Excited Rotor Whirl,” ASME J. Eng. Power, 87(4), pp. 333–344. [CrossRef]
Chupp, R. , Hendricks, R. , Lattime, S. , and Steinetz, B. , 2006, “ Sealing in Turbomachinery,” J. Propul. Power, 22(2), pp. 313–349. [CrossRef]
Schultz, R. R. , and Vance, J. M. , 1996, “ Pressure Damper Diverging Labyrinth Seals With Circumferential Partitions, and Method of Sealing,” Patent No. 5,540,447.
Takahashi, N. , Miura, H. , Narita, M. , Nishijima, N. , and Magara, Y. , 2014, “ Development of Scallop Cut Type Damper Seal for Centrifugal Compressors,” ASME Paper No. GT2014-26693.
Vance, J. M. , and Schultz, R. R. , 1993, “ A New Damper Seal for Turbomachinery,” 14th Vibration and Noise Conference, Albuquerque, NM, pp. 139–148.
Li, J. , De Choudhury, P. , and Tacques, R. , 2002, “ Seal and Bearing Upgrade for Eliminating Rotor Instability Vibration in a High Pressure Natural Gas Compressor,” ASME Paper No. GT2002-30635.
Ertas, B. H. , and Vance, J. M. , 2007, “ Rotordynamic Force Coefficients for a New Damper Seal Design,” ASME J. Tribol., 129(2), pp. 365–374. [CrossRef]
Subbiah, R. , and Choudhry, V. , 2006, “ Swirl Breaking Devices and Their Effectiveness in Reducing Rotor Instability,” Seventh IFToMM-Conference on Rotor Dynamics, Vienna, Austria, Sept. 25–28, Paper No. 173.
Vance, J. M. , and Li, J. , 1996, “ Test Results of a New Damper Seal for Vibration Reduction in Turbomachinery,” ASME J. Eng. Gas Turbines Power, 118(4), pp. 843–846. [CrossRef]
Ransom, D. , Li, J. , San Andres, L. , and Vance, J. M. , 1999, “ Experimental Force Coefficients for a Two-Bladed Labyrinth Seal and a Four-Pocket Damper Seal,” ASME J. Tribol., 121(2), pp. 370–376. [CrossRef]
Ertas, B. H. , Delgado, A. , and Vannini, G. , 2012, “ Rotordynamic Force Coefficients for Three Types of Annular Gas Seals With Inlet Preswirl and High Differential Pressure Ratio,” ASME J. Eng. Gas Turbines Power, 134(4), p. 042503. [CrossRef]
Sheng, N. , Ruggiero, E. , Devi, R. , Guo, J. , and Cirri, M. , 2011, “ Experimental and Analytical Leakage Characterization of Annular Gas Seals: Honeycomb, Labyrinth and Pocket Damper Seals,” ASME Paper No. GT2011-45217.
Vannini, G. , Cioncolini, S. , Del Vescovo, G. , and Rovini, M. , 2014, “ Labyrinth Seal and Pocket Damper Seal High Pressure Rotordynamic Test Data,” ASME J. Eng. Gas Turbines Power, 136(2), pp. 22501–22509. [CrossRef]
Li, J. , San Andrés, L. , and Vance, J. M. , 1999, “ A Bulk-Flow Analysis of Multiple-Pocket Gas Damper Seals,” ASME J. Eng. Gas Turbines Power, 121(2), pp. 355–363. [CrossRef]
Gamal, A. , 2007, “ Leakage and Rotordynamic Effects of Pocket Damper Seals and See-Through Labyrinth Seals,” Ph.D. thesis, Texas A&M University, College Station, TX. http://oaktrust.library.tamu.edu/handle/1969.1/ETD-TAMU-2084
Ertas, B. H. , and Vance, J. M. , 2007, “ The Influence of Same-Sign Cross-Coupled Stiffness on Rotordynamics,” ASME J. Vib. Acoust., 129(1), pp. 24–31. [CrossRef]
Li, J. , Kushner, F. , and De Choudhury, P. , 2002, “ Experimental Evaluation of Slotted Pocket Gas Damper Seals on a Rotating Test Rig,” ASME Paper No. GT2002-30634.
Ertas, B. H. , Gamal, A. , and Vance, J. M. , 2006, “ Rotordynamic Force Coefficients of Pocket Damper Seals,” ASME J. Turbomach., 128(4), pp. 725–737. [CrossRef]
Li, Z. , Li, J. , and Feng, Z. , 2015, “ Numerical Investigations on the Leakage and Rotordynamic Characteristics of Pocket Damper Seals–Part II: Effects of Partition Wall Type, Partition Wall Number, and Cavity Depth,” ASME J. Eng. Gas Turbines Power, 137(3), p. 032504.
Gaszner, M. , Pugachev, A. O. , Georgakis, C. , and Cooper, P. , 2013, “ Leakage and Rotordynamic Coefficients of Brush Seals With Zero Cold Clearance Used in an Arrangement With Labyrinth Fins,” ASME J. Eng. Gas Turbines Power, 135(12), p. 042503.
Pugachev, A. , Griebel, C. , Tibos, S. , and Charnley, B. , 2016, “ Performance Analysis of Hybrid Brush Pocket Damper Seals Using Computational Fluid Dynamics,” ASME Paper No. GT2016-57418.


Grahic Jump Location
Fig. 1

Pocket damper seal (PDS, left) and fully partitioned pocket damper seal (FPDS, right)

Grahic Jump Location
Fig. 2

Fully partitioned pocket damper seal geometry variations: notch configurations

Grahic Jump Location
Fig. 3

Fully partitioned pocket damper seal geometry variations: partition wall configurations

Grahic Jump Location
Fig. 4

Schematic of the no-whirl test rig with test seal casing and air supply system

Grahic Jump Location
Fig. 8

Experimental and predicted axial pressure distribution on stator wall of baseline FPDS at minimum and maximum clearance

Grahic Jump Location
Fig. 9

Experimental and predicted leakage for baseline FPDS at different inlet pressures

Grahic Jump Location
Fig. 10

Predicted leakage compared for all seal geometries

Grahic Jump Location
Fig. 11

Axial velocity component profile in outlet blade notches: flow narrowing

Grahic Jump Location
Fig. 12

Predicted stiffness coefficients compared for all seal geometries

Grahic Jump Location
Fig. 13

Predicted damping coefficients compared for all seal geometries

Grahic Jump Location
Fig. 5

Computational grid for the baseline FPDS model with sectional planes of fluid domain

Grahic Jump Location
Fig. 6

Setup of the flow domain with velocity distribution and indicative streamlines

Grahic Jump Location
Fig. 7

Rotor motion scheme used in transient simulations: forward whirl

Grahic Jump Location
Fig. 14

Predicted effective damping compared for all seal geometries



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