0
Research Papers

Rounded Fin Edge and Step Position Effects on Discharge Coefficient in Rotating Labyrinth Seals

[+] Author and Article Information
Andrea Rapisarda

Dipartimento Energia,
Politecnico di Torino,
Turin 10129, Italy
e-mail: andrea.rapisarda@polito.it

Alessio Desando

Dipartimento Energia,
Politecnico di Torino,
Turin 10129, Italy
e-mail: alessio.desando@polito.it

Elena Campagnoli

Dipartimento Energia,
Politecnico di Torino,
Turin 10129, Italy
e-mail: elena.campagnoli@polito.it

Roberto Taurino

Dipartimento Energia,
Politecnico di Torino,
Turin 10129, Italy
e-mail: roberto.taurino@polito.it

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received March 27, 2015; final manuscript received September 11, 2015; published online October 21, 2015. Assoc. Editor: Kenichiro Takeishi.

J. Turbomach 138(1), 011005 (Oct 21, 2015) (17 pages) Paper No: TURBO-15-1058; doi: 10.1115/1.4031748 History: Received March 27, 2015; Revised September 11, 2015

The design of modern aircrafts propulsion systems is strongly influenced by the important objective of environmental impact reduction. Through a great number of researches carried out in the last decades, significant improvements have been obtained in terms of lower fuel consumption and pollutant emission. Experimental tests are a necessary step to achieve new solutions that are more efficient than the current designs, even if during the preliminary design phase, a valid alternative to expensive experimental tests is the implementation of numerical models. The processing power of modern computers allows indeed the simulation of more complex and detailed phenomena than the past years. The present work focuses on the implementation of a numerical model for rotating stepped labyrinth seals installed in low-pressure turbines. These components are widely employed in sealing turbomachinery to reduce the leakage flow between rotating components. The numerical simulations were performed by using computational fluid dynamics (CFD) methodology, focusing on the leakage performances at different rotating speeds and inlet preswirl ratios. Investigations on velocity profiles into seal cavities were also carried out. To begin with, a smooth labyrinth seal model was validated by using the experimental data found in the literature. The numerical simulations were extended to the honeycomb labyrinth seals, with the validation performed on the velocity profiles. Then, the effects of two geometrical parameters, the rounded fin tip leading edge, and the step position were numerically investigated for both smooth and honeycomb labyrinth seals. The obtained results are generally in good agreement with the experimental data. The main effect found when the fin tip leading edge was rounded was a large increase in leakage flow, while the step position contribution to the flow path behavior is nonmonotone.

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

References

Braun, E. , Dullenkopf, K. , and Bauer, H. J. , 2012, “ Optimization of Labyrinth Seal Performance Combining Experimental, Numerical and Data Mining Methods,” ASME Paper No. GT2012-68077.
Denecke, J. , Dullenkopf, K. , Wittig, S. , and Bauer, H. J. , 2005, “ Experimental Investigation of the Total Temperature Increase and Swirl Development in Rotating Labyrinth Seals,” ASME Paper No. GT2005-68677.
Weinberger, T. , Dullenkopf, K. , and Bauer, H. J. , 2010, “ Influence of Honeycomb Facings on the Temperature Distribution of Labyrinth Seals,” ASME Paper No. GT2010-22069.
Waschka, W. , Wittig, S. , and Kim, S. , 1992, “ Influence of High Rotational Speeds on the Heat Transfer and Discharge Coefficients in Labyrinth Seals,” ASME J. Turbomach., 114(2), pp. 462–468. [CrossRef]
Waschka, W. , Wittig, S. , Kim, S. , and Scherer, Th. , 1993, “ Heat Transfer and Leakage in High-Speed Rotating Stepped Labyrinth Seals,” Heat Transfer and Cooling in Gas Turbines: Propulsion and Energetics Panel 80th Symposium, Antalya, Turkey, Oct. 12–16, AGARD-CP-527, p. 26.
Denecke, J. , Dullenkopf, K. , and Wittig, S. , 2004, “ Influence of Pre-Swirl and Rotation on Labyrinth Seal Leakage,” 10th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery (ISROMAC-10), Honolulu, HI, Mar. 7–11, Paper No. ISROMAC 10-2004-105.
Denecke, J. , Färber, J. , Dullenkopf, K. , and Bauer, H. J. , 2005, “ Dimensional Analysis and Scaling of Rotating Seals,” ASME Paper No. GT2005-68676.
Yan, X. , Li, J. , and Feng, Z. , 2011, “ Effects of Sealing Clearance and Stepped Geometries on Discharge and Heat Transfer Characteristics of Stepped Labyrinths Seals,” Proc. Inst. Mech. Eng., Part A, 225(4), pp. 521–538. [CrossRef]
Wang, Y. , Young, C. , Snowsill, G. , and Scanlon, T. , 2004, “ Study of Airflow Features Through Step Seals in the Presence of Dis-Engagement Due to Axial Movement,” ASME Paper No. GT2004-53056.
Willenborg, K. , Kim, S. , and Wittig, S. , 2001, “ Effects of Reynolds Number and Pressure Ratio on Leakage Loss and Heat Transfer in a Stepped Labyrinth Seal,” ASME J. Turbomach., 123(4), pp. 815–822. [CrossRef]
Martin, H. M. , 1908, “ Labyrinth Packings,” Engineering, 85(10), pp. 35–38.
Kearton, W. J. , and Keh, T. H. , 1952, “ Leakage of Air Through Labyrinth Glands of Staggered Type,” Proc. Inst. Mech. Eng., Ser. A, 166(1), pp. 180–195. [CrossRef]
Yan, X. , Li, J. , and Feng, Z. , 2010, “ Effects of Inlet Pre-Swirl and Cell Diameter and Depth on Honeycomb Seal Characteristics,” ASME J. Eng. Gas Turbines Power, 132(12), p. 122506. [CrossRef]
ANSYS, 2013, “ ANSYS CFX-Solver Theory Guide,” ANSYS, Inc., Canonsburg, PA.
Du, Y. , 2010, “ Numerical Simulation of Mechanical and Thermal Fluid-Structure Interaction in Labyrinth Seals,” Ph.D. thesis, Technischen Universität Darmstadt, Darmstadt, Germany.
Schramm, V. , Willenborg, K. , Kim, S. , and Wittig, S. , 2002, “ Influence of a Honeycomb Facing on the Flow Through a Stepped Labyrinth Seal,” ASME J. Eng. Gas Turbines Power, 124(1), pp. 140–146. [CrossRef]
Parker FluidPower, 1979, “ Design Engineers Handbook,” Parker, Cleveland, OH, Bulletin No. 0224-B1.

Figures

Grahic Jump Location
Fig. 1

Forward- and backward-stepped labyrinth seal

Grahic Jump Location
Fig. 2

Boundary conditions

Grahic Jump Location
Fig. 3

Clearance grid thickenings adopted: MESH 1 (left), MESH 2 (center), and MESH 3 (right)

Grahic Jump Location
Fig. 4

MESH 3, convergent flow

Grahic Jump Location
Fig. 5

Honeycomb cells grid

Grahic Jump Location
Fig. 6

Convergent smooth labyrinth seal, π = 1.05; k = 0 (left) and k = 0.3 (right)

Grahic Jump Location
Fig. 7

Axial (left) and circumferential (right) velocity profiles at x1 for smooth convergent labyrinth seal, k=0

Grahic Jump Location
Fig. 8

Axial (left) and circumferential (right) velocity profiles at x2 for smooth convergent labyrinth seal, k=0.3

Grahic Jump Location
Fig. 9

Convergent honeycomb labyrinth seal, π=1.05; k=0 (left) and k=0.3 (right)

Grahic Jump Location
Fig. 10

Axial (left) and circumferential (right) velocity profiles at x2 for honeycomb convergent labyrinth seal, k=0.3

Grahic Jump Location
Fig. 11

Divergent smooth labyrinth seal, π=1.05; k=0 (left) and k=0.3 (right)

Grahic Jump Location
Fig. 12

Axial (left) and circumferential (right) velocity profiles at  x3 for smooth divergent labyrinth seal, k=0.3

Grahic Jump Location
Fig. 13

Divergent honeycomb labyrinth seal,  π=1.05; k=0 (left) and k=0.3 (right)

Grahic Jump Location
Fig. 14

Axial (left) and circumferential (right) velocity profiles at x3 for honeycomb divergent labyrinth seal, k=0.3

Grahic Jump Location
Fig. 15

Square (left) and rounded (right) fin tip leading edge

Grahic Jump Location
Fig. 16

Rounded fin tip leading edge: nonrotating discharge coefficient for convergent flow labyrinth seals

Grahic Jump Location
Fig. 17

Rounded fin tip leading edge: vena contracta effect on second fin tip for smooth (up) and honeycomb (down) labyrinth seals, convergent flow, nonrotating conditions

Grahic Jump Location
Fig. 18

Rounded fin tip leading edge: axial (left) and circumferential (right) velocity profiles at  x2 for smooth convergent labyrinth seal

Grahic Jump Location
Fig. 19

Rounded fin tip leading edge: axial (left) and circumferential (right) velocity profiles at  x2 for honeycomb convergent labyrinth seal

Grahic Jump Location
Fig. 20

Rounded fin tip leading edge: nonrotating discharge coefficient for divergent flow labyrinth seals

Grahic Jump Location
Fig. 22

Rounded fin tip leading edge: axial (left) and circumferential (right) velocity profiles at  x3 for smooth divergent labyrinth seal

Grahic Jump Location
Fig. 23

Rounded fin tip leading edge: axial (left) and circumferential (right) velocity profiles at  x3 for honeycomb divergent labyrinth seal

Grahic Jump Location
Fig. 24

Step position: nonrotating discharge coefficient for convergent flow labyrinth seals

Grahic Jump Location
Fig. 25

Step position: eddy viscosity on nonrotating convergent smooth labyrinth seals

Grahic Jump Location
Fig. 26

Step position: velocity contour for convergent smooth labyrinth seals

Grahic Jump Location
Fig. 27

Step position: velocity contour for convergent honeycomb labyrinth seals

Grahic Jump Location
Fig. 28

Step position: axial (left) and circumferential (right) velocity profiles at  x2 for smooth convergent labyrinth seal

Grahic Jump Location
Fig. 29

Step position: axial (left) and circumferential (right) velocity profiles at  x2 for honeycomb convergent labyrinth seal

Grahic Jump Location
Fig. 30

Step position: nonrotating discharge coefficient for divergent flow labyrinth seals

Grahic Jump Location
Fig. 31

Step position: velocity contour for divergent smooth labyrinth seals

Grahic Jump Location
Fig. 32

Step position: velocity contour for divergent honeycomb labyrinth seals

Grahic Jump Location
Fig. 33

Step position: axial (left) and circumferential (right) velocity profiles at  x3 for smooth divergent labyrinth seal

Grahic Jump Location
Fig. 34

Step position: axial (left) and circumferential (right) velocity profiles at  x3 for honeycomb divergent labyrinth seal

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