Research Papers: Gas Turbines: Structures and Dynamics

Static and Rotordynamic Characteristics for a New Hole-Pattern Annular Gas Seal Design Incorporating Larger Diameter Holes

[+] Author and Article Information
Michael Vannarsdall

Graduate Research Assistant
Texas A&M University,
College Station, TX 77845

Dara W. Childs

Director Turbolab/Jordan Chair Professor
Department of Mechanical Engineering,
Texas A&M University,
College Station, TX 77845
e-mail: dchilds@tamu.edu

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 6, 2012; final manuscript received September 11, 2013; published online November 4, 2013. Editor: David Wisler.

J. Eng. Gas Turbines Power 136(2), 022507 (Nov 04, 2013) (7 pages) Paper No: GTP-12-1260; doi: 10.1115/1.4025536 History: Received July 06, 2012; Revised September 11, 2013

To reduce manufacturing cost and time, a new larger-diameter hole-pattern seal incorporating hole diameters of 12.27 mm, versus prior hole diameters of 3.175 mm has been proposed. The 12.27 mm hole-diameter seal had substantially better stability performance with higher effective damping and a markedly lower crossover frequency. It had negative direct stiffness coefficients at low frequency, while the 3.175 mm hole-diameter seal did not. Predictions for the rotordynamic coefficients of this new seal were made based on a two-control-volume model developed by Kleynhans and Childs in 1997. The two control volumes consisted of a through-flow control-volume and a control-volume B that extended from the surface of the stator at the top of the holes to the bottom of holes. Predictions agreed poorly with measured results, because the model used, assumes gas flows only radially within control-volume B. With the large hole-diameters axial and circumferential flow is readily accomplished. Compared to the prior 3.175 mm hole-diameter seals, the 12.27 mm hole-diameter seal design leaked approximately 37.5% more which probably precludes its commercial application. Leakage for the seal was well predicted. Although the larger hole diameters were initially proposed to reduce costs, the fabrication was more challenging than originally thought. The larger holes could not be manufactured with a single pass. Hence, manufacturing costs and time were not reduced.

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von Progenau, G. L., 1982, “Damping Seals for Turbomachinery,” Marshall Space Flight Center, Huntsville, AL.
Scharrer, J. K., 1989, “Discussion: `Annular Honeycomb Seals: Test Results for Leakage and Rotordynamic Coefficients; Comparisons to Labyrinth and Smooth Configurations' (Childs, D., Elrod, D., and Hale, K., 1989, ASME J. Tribol., 111, pp. 293–300),” ASME J. Tribol.111(2), pp. 300–301. [CrossRef]
Yu, Z., and Childs, D., 1998, “A Comparison of Experimental Rotordynamic Coefficients and Leakage Characteristics Between Hole-Pattern Gas Damper Seals and a Honeycomb Seal,” ASME J. Eng. Gas Turbines Power, 120(4), pp. 778–783. [CrossRef]
Childs, D., and Wade, J., 2004, “Rotordynamic-Coefficient and Leakage Characteristics for Hole-Pattern-Stator Annular Gas Seals-Measurements Versus Predictions,” ASME J. Tribol., 126(2), pp. 326–333. [CrossRef]
Kleynhans, G., and Childs, D., 1997, “The Acoustic Influence of Cell Depth on the Rotordynamic Characteristics of Smooth-Rotor/Honeycomb-Stator Annular Gas Seals,” ASME J. Eng. Gas Turbines Power, 119(4), pp. 949–957. [CrossRef]
Asiravatham, T., and Childs, D., 2011, “Friction Factor Behavior From Flat-Plate Tests of 12.15 mm Diameter Hole-Pattern Roughened Surfaces,” ASME 2011 Turbo Expo, Vancouver, BC, Canada, June 6–10, ASME Paper No. GT2011-45213, pp. 247–255. [CrossRef]
Glienicke, J., 1966, “Experimental Investigation of Stiffness and Damping Coefficients of Turbine Bearings and Their Application to Instability Predictions,” Proc. IMechE, 181(2), pp. 116–129. [CrossRef]
Picardo, A., and Childs, D., 2005, “Rotordynamic Coefficients for a Teeth-on-Stator Labyrinth Seals at 70 Bar Supply Pressures—Measurements Versus Theory and Comparisons to a Honeycomb Seal,” ASME J. Gas Turbines, 127(4), pp. 843–855. [CrossRef]
Childs, D., and Shin, Yoon-Shik, 2006, “A Design to Increase the Static Stiffness of Hole Pattern Stator Gas Seals,” Proceedings of the ASME Turbo Expo 2006: Power for Land, Sea, and Air, Barcelona, Spain, May 8–11, ASME Paper No. GT2006-90778, pp. 1279–1284. [CrossRef]
San Andrés, L., 1991, “Analysis of Variable Fluid Properties, Turbulent Annular Seals,” ASME J. Tribol., 113(4), 694–702. [CrossRef]
Yamada, Y., 1962, “Resistance of Flow Through an Annulus With an Inner Rotating Cylinder,” Bull. J.S.M.E., 5(1), pp. 302–310. [CrossRef]
Chochua, G., and Soulas, T. A., 2007, “Numerical Modeling of Rotordynamic Coefficients for Deliberately Roughened Stator Gas Annular Seals,” ASME J. Tribology, 129(2), pp. 424–429. [CrossRef]


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Fig. 1

Hole-pattern tested by Childs and Wade [2]

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Fig. 2

Large-diameter-hole pattern

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Fig. 3

Sectional view of the test section

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Fig. 4

Test stator and cross-sectional cut C-C

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Fig. 6

Pitot tube and static pressure probe to measure inlet preswirl

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Fig. 7

Two-control volume model [5]

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Fig. 8

K measured and predicted

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Fig. 9

k measured and predicted

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Fig. 10

C measured and predicted

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Fig. 11

c measured and predicted

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Fig. 12

Leakage measure and predicted

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Fig. 13

Leakage for HPLD and HPT seal

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Fig. 14

K*  for HPLD and HPT seal

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Fig. 15

k for HPLD and HPT seal

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Fig. 16

C for HPLD and HPT seal

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Fig. 17

c for HPLD and HPT seal

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Fig. 18

Keff for HPLD and HPT seal

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Fig. 19

Ceff for HPLD and HPT seal



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