Research Papers: Gas Turbines: Structures and Dynamics

The Impact of Hole Depth on the Rotordynamic and Leakage Characteristics of Hole-Pattern-Stator Gas Annular Seals

[+] Author and Article Information
Dara W. Childs

The Leland T. Jordan Chair
of Mechanical Engineering
e-mail: dchilds@tamu.edu

Stephen Arthur

Graduate Research Assistant
e-mail: sarthur88@gmail.com
Turbomachinery Laboratory,
Texas A&M University,
College Station, TX 77843

Naitik J. Mehta

Mechanical Engineer-Rotating Equipment,
Bechtel OG&C,
Houston, TX 77056
e-mail: nmehta1@bechtel.com

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 30, 2013; final manuscript received August 14, 2013; published online December 10, 2013. Editor: David Wisler.

J. Eng. Gas Turbines Power 136(4), 042501 (Dec 10, 2013) (6 pages) Paper No: GTP-13-1282; doi: 10.1115/1.4025888 History: Received July 30, 2013; Revised August 14, 2013

Test results are presented for rotordynamic characteristics of hole-pattern-stator annular gas seals at a 70 bar supply pressures with a running speed of 20,200 rpm. Leakage results are presented for these conditions and the additional speeds: 10,200 and 15,300 rpm. Hole-depth is the principal test variable of interest. Most published annular test data for these seals have a hole diameter of 3.175 mm and a hole depth of 3.302 mm. For this work, with the 3.175 mm hole diameter, additional results are presented for shallow (1.905 mm) and deep (6.604 mm) hole depths. Test results show a pronounced dependence of leakage and rotordynamic behavior on hole depth. Test results show much better leakage performance for the shallow-hole-depth seal in both leakage and rotordynamic performance. Compressor manufacturers and users will need to decide whether this observed performance improvement is worth trying in real machines.

Copyright © 2014 by ASME
Topics: Stators , Leakage , Damping
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Fig. 1

Test seal hole pattern [3]

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Fig. 2

Effect of varying hd on friction factor for smooth-on-hole configuration (Pin = 84 bar, Ø = 3.175 mm, and plate clearance = 0.635 mm) [3]

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Fig. 3

Cross section of the air seal test rig [1]

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Fig. 4

Test stator assembly [1]

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Fig. 5

Cross section view of the preswirl rings and pitot tube location [1]

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Fig. 6

Measured m· results for three hole depths

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Fig. 7

Measured Kxx*(Ω) results for three hole depths

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Fig. 8

Measured Kxy*(Ω) results for three hole depths

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Fig. 9

Measured Cxx*(Ω) results for three hole depths

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Fig. 10

Measured Ceff*(Ω) results for three hole depths



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