The analysis is presented for the computational fluid dynamics (CFD)-based modeling of short labyrinth gas seals. Seal leakage performance can be reliably predicted with CFD for a wide operating range and various sealing configurations. Prediction of seal influence on the rotordynamic stability, however, is a challenging task requiring relatively high computer processing power. A full 3D eccentric CFD model of a short staggered three-tooth-on-stator labyrinth seal is built in ANSYS CFX. An extensive grid independence study is carried out showing influence of the grid refinement on the stiffness coefficients. Three methods for the prediction of stiffness and damping coefficients as well as the effect of turbulence modeling, boundary conditions, and solver parameters are presented. The rest of the paper shows the results of a parameter variation (inlet pressure, preswirl, and shaft rotational speed) for two labyrinth seals with a tooth radial clearance of 0.5 mm and 0.27 mm, respectively. The latter was compared with experimental data in Pugachev and Deckner, 2010, “Analysis of the Experimental and CFD-Based Theoretical Methods for Studying Rotordynamic Characteristics of Labyrinth Gas Seals,” Proceedings of ASME Turbo Expo 2010, Paper No. GT2010-22058.

References

References
1.
Pugachev
,
A.
, and
Deckner
,
M.
, 2010, “
Analysis of the Experimental and CFD-Based Theoretical Methods for Studying Rotordynamic Characteristics of Labyrinth Gas Seals
,”
Proceedings of ASME Turbo Expo 2010
, Paper No. GT2010–22058.
2.
Nordmann
,
R.
,
Dietzen
,
F.
, and
Weiser
,
H.
, 1989, “
Calculation of Rotordynamic Coefficients and Leakage for Annular Gas Seals by Means of Finite Difference Techniques
,”.
ASME J. Tribol.
,
111
, pp.
545
552
.
3.
Athavale
,
M.
,
Przekwas
,
A.
, and
Hendricks
,
R.
, 1992, “
A Finite Volume Numerical Method to Calculate Fluid Forces and Rotordynamic Coefficients in Seals
,”
Proceedings of the 28th AIAA Joint Propulsion Conference
, AIAA Paper No. 92–3712.
4.
Rhode
,
D.
,
Hensel
,
S.
, and
Guidry
,
M.
, 1992, “
Labyrinth Seal Rotordynamic Forces Using a Three-Dimensional Navier-Stokes Code
,”
ASME J. Tribol.
,
114
, pp.
683
689
.
5.
Arghir
,
M.
, and
Frêne
,
J.
, 1999, “
A Quasi-Two-Dimensional Method for the Rotordynamic Analysis of Centered Labyrinth Liquid Seals
,”
ASME J. Eng. Gas Turbines Power
,
121
, pp.
144
152
.
6.
Huang
,
D.
, and
Li
,
X.
, 2004, “
Rotordynamic Characteristics of a Rotor with Labyrinth Gas Seals. Part 1: Comparison with Childs Experiments
,”,
Proc. Inst. Mech. Eng., Part A
,
218
(
3
), pp.
171
177
.
7.
Moore
,
J.
, 2003, “
Three-Dimensional CFD Rotordynamic Analysis of Gas Labyrinth Seals
,”
ASME J. Vibr. Acoust.
,
125
, pp.
427
433
.
8.
Schettel
,
J.
,
Deckner
,
M.
,
Kwanka
,
K.
,
Lüneburg
,
B.
, and
Nordmann
,
R.
, 2005, “
Rotordynamic Coefficients of Labseals for Turbines—Comparing CFD Results with Experimental Data on a Comb-Grooved Labyrinth
,”
Proceedings of ASME Turbo Expo
, Paper No. GT2005–68732.
9.
Hirano
,
T.
,
Guo
,
Z.
, and
Kirk
,
R.
, 2005, “
Application of Computational Fluid Dynamics Analysis for Rotating Machinery—Part II: Labyrinth Seal Analysis
,”
ASME J. Eng. Gas Turbines Power
,
127
, pp.
820
826
.
10.
Wagner
,
N.
,
Steff
,
K.
,
Gausmann
,
R.
, and
Schmidt
,
M.
, 2009, “
Investigation on the Dynamic Coefficients of Impeller Eye Labyrinth Seals
,”
Proceedings of the Thirty-Eighth Turbomachinery Symposium
,
Texas A&M University
,
College Station, TX
, pp.
53
69
.
11.
Moore
,
J.
,
Ransom
,
D.
, and
Viana
,
F.
, 2011, “
Rotordynamic Force Prediction of Centrifugal Compressor Impellers Using Computational Fluid Dynamics
,”
ASME J. Eng. Gas Turbines Power
,
133
, pp.
042504
10
.
12.
Thorat
,
M.
, and
Childs
,
D.
, 2010, “
Predicted Rotordynamic Behavior of a Labyrinth Seal as Rotor Surface Speed Approaches Mach 1
,”
ASME J. Eng. Gas Turbines Power
,
132
, pp.
112504
8
.
13.
Vannini
,
G.
,
Thorat
,
M.
,
Childs
,
D.
, and
Libraschi
,
M.
, 2010, “
Impact of Frequency Dependence of Gas Labyrinth Seal Rotordynamic Coefficients on Centrifugal Compressor Stability
,”
Proceedings of ASME Turbo Expo
, Paper No. GT2010–22039.
14.
Childs
,
D.
, 1993,
Turbomachinery Rotordynamics: Phenomena, Modeling, and Analysis
,
Wiley
,
New York
.
15.
Lund
,
J.
, 1987, “
Review of the Concept of Dynamic Coefficients for Fluid Film Journal Bearings
,”
ASME J. Tribol.
,
109
, pp.
37
41
.
16.
Adams
,
M. L. J.
, 2001,
Rotating Machinery Vibration; From Analysis to Troubleshooting
,
Marcel Dekker
,
New York
.
17.
Kwanka
,
K.
, 2000, “
Dynamic Coefficients of Stepped Labyrinth Gas Seals
ASME J. Eng. Gas Turbines Power
,
122
, pp.
473
477
.
18.
Kwanka
,
K.
, 2007, “
Rotordynamic Coefficients of Short Labyrinth Gas Seals—General Dependency on Geometric and Physical Parameters
,”
Tribol. Trans.
,
50
(
4
), pp.
558
563
.
19.
Pugachev
,
A.
, 2009, “
CFD Optimization of Liquid Annular Seals for Leakage and Rotordynamics Improvement
,”
Proceedings of ASME Turbo Expo
, Paper No. GT2009–59173.
20.
Menter
,
F.
, 1994, “
Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications
,”
AIAA J.
,
32
(
8
), pp.
1598
1605
.
21.
Kim
,
N.
, and
Rhode
,
D.
, 2003, “
Refined Turbulence Modeling for Swirl Velocity in Turbomachinery Seals
,”
Int. J. Rotating Mach.
,
9
, pp.
451
459
.
22.
Spalart
,
P. R.
, and
Shur
,
M.
, 1997, “
On the Sensitization of Turbulence Models to Rotation and Curvature
,”
Aerosp. Sci. Technol.
,
1
(
5
), pp.
297
302
.
23.
Smirnov
,
P.
, and
Menter
,
F.
, 2008, “
Sensitization of the SST Turbulence Model to Rotation and Curvature by Applying the Spalart-Shur Correction Term
,”
Proceedings of ASME Turbo Expo
, Paper No. GT2008–50480.
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