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Research Papers: Gas Turbines: Turbomachinery

A Comparison of Single and Double Lip Rim Seal Geometries

[+] Author and Article Information
Svilen S. Savov

Whittle Laboratory,
Department of Engineering,
University of Cambridge,
Cambridge CB3 0DY, UK
e-mail: sss44@cam.ac.uk

Nicholas R. Atkins

Whittle Laboratory,
Department of Engineering,
University of Cambridge,
Cambridge CB3 0DY, UK
e-mail: nra27@cam.ac.uk

Sumiu Uchida

Technology and Innovation HQ,
Mitsubishi Heavy Industries Ltd.,
5-717-1 Fukahori-machi,
Nagasaki 851-0392, Japan
e-mail: sumiu_uchida@mhi.co.jp

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received November 24, 2016; final manuscript received May 3, 2017; published online July 19, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(11), 112601 (Jul 19, 2017) (13 pages) Paper No: GTP-16-1545; doi: 10.1115/1.4037027 History: Received November 24, 2016; Revised May 03, 2017

The effect of the purge flow, engine-like blade pressure field, and mainstream flow coefficient are studied experimentally for a single and double lip rim seal. Compared to the single lip, the double lip seal requires less purge flow for similar levels of cavity seal effectiveness. Unlike the double lip seal, the single lip seal is sensitive to overall Reynolds number, the addition of a simulated blade pressure field, and large-scale nonuniform ingestion. In the case of both seals, unsteady pressure variations attributed to shear layer interaction between the mainstream and rim seal flows appear to be important for ingestion at off-design flow coefficients. The double lip seal has both a weaker vane pressure field in the rim seal cavity and a smaller difference in seal effectiveness across the lower lip than the single lip seal. As a result, the double lip seal is less sensitive in the rotor–stator cavity to changes in shear layer interaction and the effects of large-scale circumferentially nonuniform ingestion. However, the reduced flow rate through the double lip seal means that the outer lip has increased sensitivity to shear layer interactions. Overall, it is shown that seal performance is driven by both the vane/blade pressure field and the gradient in seal effectiveness across the inner lip. This implies that accurate representation of both, the pressure field and the mixing due to shear layer interaction, would be necessary for more reliable modeling.

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References

Bayley, F. J. , and Owen, J. M. , 1970, “ The Fluid Dynamics of a Shrouded Disk System With a Radial Outflow of Coolant,” J. Eng. Power, 92(3), pp. 335–341. [CrossRef]
Phadke, U. , and Owen, J. , 1983, “ An Investigation of Ingress for an ‘Air-Cooled’ Shrouded Rotating Disk System With Radial-Clearance Seals,” J. Eng. Power, 105(1), pp. 178–183. [CrossRef]
Phadke, U. , and Owen, J. , 1988, “ Aerodynamic Aspects of the Sealing of Gas-Turbine Rotor–Stator Systems—Part 1: The Behavior of Simple Shrouded Rotating-Disk Systems in a Quiescent Environment,” Int. J. Heat Fluid Flow, 9(2), pp. 98–105. [CrossRef]
Bhavnani, S. H. , Khodadadi, J. M. , Goodling, J. S. , and Waggott, J. , 1992, “ An Experimental Study of Fluid Flow in Disk Cavities,” ASME J. Turbomach., 114(2), pp. 454–461. [CrossRef]
Abe, T. , Kikuchi, J. , and Takeuchi, H. , 1979, “ An Investigation of Turbine Disk Cooling (Experimental Investigation and Observation of Hot Gas Flow Into a Wheel Space),” 13th International Congress on Combustion Engines, Vienna, Austria, May 7–10, Paper No. GT-30. http://ci.nii.ac.jp/naid/80000465275
Phadke, U. , and Owen, J. , 1988, “ Aerodynamic Aspects of the Sealing of Gas-Turbine Rotor–Stator Systems—Part 2: The Performance of Simple Seals in a Quasi-Axisymmetric External Flow,” Int. J. Heat Fluid Flow, 9(2), pp. 106–112. [CrossRef]
Phadke, U. , and Owen, J. , 1988, “ Aerodynamic Aspects of the Sealing of Gas-Turbine Rotor–Stator Systems—Part 3: The Effect of Nonaxisymmetric External Flow on Seal Performance,” Int. J. Heat Fluid Flow, 9(2), pp. 113–117. [CrossRef]
Graber, D. , Daniels, W. , and Johnson, B. , 1987, “ Disk Pumping Test,” Air Force Wright Aeronautical Laboratories, Wright-Patterson AFB, OH, Technical Report No. AFWAL-TR-87-2050. http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA187199
Dadkhah, S. , Turner, A. B. , and Chew, J. W. , 1992, “ Performance of Radial Clearance Rim Seals in Upstream and Downstream Rotor–Stator Wheelspaces,” ASME J. Turbomach., 114(2), pp. 439–445. [CrossRef]
Bohn, D. , Johann, E. , and Kruger, U. , 1995, “ Experimental and Numerical Investigations of Aerodynamic Aspects of Hot Gas Ingestion in Rotor–Stator Systems With Superimposed Cooling Mass Flow,” ASME Paper No. 95-GT-143.
Zhou, D. W. , Roy, R. P. , Wang, C.-Z. , and Glahn, J. A. , 2011, “ Main Gas Ingestion in a Turbine Stage for Three Rim Cavity Configurations,” ASME J. Turbomach., 133(3), p. 031023. [CrossRef]
Green, T. , and Turner, A. B. , 1994, “ Ingestion Into the Upstream Wheelspace of an Axial Turbine Stage,” ASME J. Turbomach., 116(2), pp. 327–332. [CrossRef]
Bohn, D. , Rudzinski, B. , and Surken, N. , 2000, “ Experimental and Numerical Investigation of the Influence of Rotor Blades on Hot Gas Ingestion Into the Upstream Cavity of an Axial Turbine Stage,” ASME Paper No. 2000-GT-0284.
Bohn, D. , Rudzinski, B. , and Surken, N. , 1999, “ Influence of Rim Seal Geometry on Hot Gas Ingestion Into the Upstream Cavity of an Axial Turbine,” ASME Paper No. 99-GT-248.
Gentilhomme, O. , Hills, N. J. , Turner, A. B. , and Chew, J. W. , 2003, “ Measurement and Analysis of Ingestion Through a Turbine Rim Seal,” ASME J. Turbomach., 125(3), pp. 505–512. [CrossRef]
Sangan, C. M. , Lalwani, Y. , Owen, J. M. , and Lock, G. D. , 2011, “ Experimental Measurements of Ingestion Through Turbine Rim Seals—Part 2: Rotationally-Induced Ingress,” ASME Paper No. GT2011-45310.
Balasubramanian, J. , Pathak, P. S. , Thiagarajan, J. K. , Singh, P. , Roy, R. P. , and Mirzamoghadam, A. V. , 2015, “ Experimental Study of Ingestion in the Rotor–Stator Disk Cavity of a Subscale Axial Turbine Stage,” ASME J. Turbomach., 137(9), p. 091010. [CrossRef]
Chew, J. W. , Green, T. , and Turner, A. B. , 1994, “ Rim Sealing of Rotor–Stator Wheelspaces in the Presence of External Flow,” ASME Paper No. 94-GT-126.
Reichert, A. W. , and Lieser, D. , 1999, “ Efficiency of Air-Purged Rotor–Stator Seals in Combustion Turbine Engines,” ASME Paper No. 99-GT-250.
Bohn, D. , and Wolff, M. , 2003, “ Improved Formulation to Determine Minimum Sealing Flow—Cw, min—for Different Sealing Configurations,” ASME Paper No. GT2003-38465.
Scanlon, T. , Wilkes, J. , Bohn, D. , and Gentilhomme, O. , 2004, “ A Simple Method for Estimating Ingestion of Annulus Gas Into a Turbine Rotor Stator Cavity in the Presence of External Pressure Variations,” ASME Paper No. GT2004-53097.
Johnson, B. V. , Jakoby, R. , Bohn, D. , and Cunat, D. , 2009, “ A Method for Estimating the Influence of Time-Dependent Vane and Blade Pressure Fields on Turbine Rim Seal Ingestion,” ASME J. Turbomach., 131(2), p. 021005. [CrossRef]
Owen, J. , Pountney, O. , and Lock, G. , 2012, “ Prediction of Ingress Through Turbine Rim Seals—Part 2: Combined Ingress,” ASME J. Turbomach., 134(3), p. 031013. [CrossRef]
O'Mahoney, T. S. D. , Hills, N. J. , Chew, J. W. , and Scanlon, T. , 2010, “ Large-Eddy Simulation of Rim Seal Ingestion,” ASME Paper No. GT2010-22962.
Cao, C. , Chew, J. W. , Millington, P. R. , and Hogg, S. I. , 2004, “ Interaction of Rim Seal and Annulus Flows in an Axial Flow Turbine,” ASME J. Eng. Gas Turbines Power, 126(4), pp. 786–793. [CrossRef]
Jakoby, R. , Zierer, T. , Lindblad, K. , Larsson, J. , deVito, L. , Bohn, D. , Funcke, J. , and Decker, A. , 2004, “ Numerical Simulation of the Unsteady Flow Field in an Axial Turbine Rim Seal Configuration,” ASME Paper No. GT2004-53829.
Wang, C.-Z. , Mathiyalagan, S. P. , Johnson, B. V. , Glahn, J. A. , and Cloud, D. F. , 2012, “ Rim Seal Ingestion in a Turbine Stage From 360-Degree Time-Dependent Numerical Simulations,” ASME Paper No. GT2012-68193.
Mirzamoghadam, A. V. , Kanjiyani, S. , Riahi, A. , Vishnumolakala, R. , and Gundeti, L. , 2014, “ Unsteady 360 Computational Fluid Dynamics Validation of a Turbine Stage Mainstream/Disk Cavity Interaction,” ASME J. Turbomach., 137(1), p. 011008. [CrossRef]
Roy, R. P. , Feng, J. , Narzary, D. , and Paolillo, R. E. , 2005, “ Experiment on Gas Ingestion Through Axial-Flow Turbine Rim Seals,” ASME J. Eng. Gas Turbines Power, 127(3), pp. 573–582. [CrossRef]
Boudet, J. , Hills, N. J. , and Chew, J. W. , 2006, “ Numerical Simulation of the Flow Interaction Between Turbine Main Annulus and Disc Cavities,” ASME Paper No. GT2006-90307.
Chilla, M. , Hodson, H. , and Newman, D. , 2013, “ Unsteady Interaction Between Annulus and Turbine Rim Seal Flows,” ASME J. Turbomach., 135(5), p. 051024. [CrossRef]
Rabs, M. , Benra, F. , Dohmen, H. , and Schneider, O. , 2009, “ Investigation of Flow Instabilities Near the Rim Cavity of a 1.5 Stage Gas Turbine,” ASME Paper No. GT2009-59965.
Popovic, I. , and Hodson, H. P. , 2012, “ The Effects of a Parametric Variation of the Rim Seal Geometry on the Interaction Between Hub Leakage and Mainstream Flows in HP Turbines,” ASME Paper No. GT2012-68025.
Popovic, I. , and Hodson, H. P. , 2012, “ Improving Turbine Stage Efficiency and Sealing Effectiveness Through Modifications of the Rim Seal Geometry,” ASME Paper No. GT2012-68026.
Mirzamoghadam, A. V. , Giebert, D. , Molla-Hosseini, K. , and Bedrosyan, L. , 2012, “ The Influence of HPT Forward Disc Cavity Platform Axial Overlap Geometry on Mainstream Ingestion,” ASME Paper No. GT2012-68429.
Lowry, S. A. , and Keeton, L. W. , 1987, “ Space Shuttle Main Engine High Pressure Fuel Pump Aft Platform Seal Cavity Flow Analysis,” NASA Marshall Space Flight Center, Huntsville, AL, Technical Paper No. NASA-TP-2685. https://ntrs.nasa.gov/search.jsp?R=19870007567
Guo, Z. , Rhode, D. L. , and Davis, F. M. , 1996, “ Computed Eccentricity Effects on Turbine Rim Seals at Engine Conditions With a Mainstream,” ASME J. Turbomach., 118(1), pp. 143–152. [CrossRef]
Brandvik, T. , and Pullan, G. , 2011, “ An Accelerated 3D Navier–Stokes Solver for Flows in Turbomachines,” ASME J. Turbomach., 133(2), p. 021025. [CrossRef]
Savov, S. , 2015, “ An Experimental Investigation of Gas Turbine Rotor–Stator Cavity Purge Flow,” Ph.D. thesis, University of Cambridge, Cambridge, UK.
Sangan, C. M. , Lalwani, Y. , Owen, J. M. , and Lock, G. D. , 2012, “ Experimental Measurements of Ingestion Through Turbine Rim Seals—Part 3: Single and Double Seals,” ASME Paper No. GT2012-68493.
Scobie, J. A. , Teuber, R. , Li, Y. S. , Sangan, C. M. , Wilson, M. , and Lock, G. D. , 2015, “ Design of an Improved Turbine Rim-Seal,” ASME Paper No. GT2015-42327.
Okita, Y. , Nishiura, M. , Yamawaki, S. , and Hironaka, Y. , 2005, “ A Novel Cooling Method for Turbine Rotor–Stator Rim Cavities Affected by Mainstream Ingress,” ASME J. Eng. Gas Turbines Power, 127(4), pp. 798–806. [CrossRef]
Sangan, C. M. , Scobie, J. A. , Owen, J. M. , Lock, G. D. , Tham, K. M. , and Laurello, V. P. , 2014, “ Performance of a Finned Turbine Rim Seal,” ASME Paper No. GT2014-25626.
ISO/IEC, 2009, “ Guide 98-1:2009 Uncertainty of Measurement—Part 1: Introduction to the Expression of Uncertainty in Measurement,” Geneva, Switzerland, Standard No. ISO/IEC FDGuide 98-1. https://infostore.saiglobal.com/store/Details.aspx/details.aspx?ProductID=1137593
Sangan, C. M. , Lalwani, Y. , Owen, J. M. , and Lock, G. D. , 2013, “ Experimental Measurements of Ingestion Through Turbine Rim Seals—Part 5: Fluid Dynamics of Wheel-Space,” ASME Paper No. GT2013-94148.

Figures

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Fig. 1

Test rig schematic and potential ingress/egress patterns

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Fig. 2

(a) CP from steady RANS CFD at measured rig boundary conditions and Mis = 0.64 compared to measurements at both Mis = 0.64 and 0.2. Data are located on the hub line, 0.02cx downstream of the vane trailing edge. Steady RANS CFD results with engine geometry and boundary conditions are shown for comparison. (b) Comparison of CP,rel from steady RANS CFD between the engine and stubby blade just downstream of the mixing plane at a radial height of 40% rig span, 12.5% span on the engine vane.

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Fig. 3

Sectional views of single lip and double lip seals. Not to scale.

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Fig. 4

Table of experimental studies performed on the single lip and double lip seals

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Fig. 5

Schematic illustration of sealing parameter, Φ, and mainstream flow coefficient, ϕ

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Fig. 6

εc versus Φ curves for the single lip and double lip seals at high and low Re conditions with and without blades, at an engine-matched mainstream flow coefficient. Double lip seal measurements without mainstream flow are also plotted.

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Fig. 7

Unbladed single lip seal: normalized pressure, P¯, and seal effectiveness, εc, across two vane pitches in the rim seal and rotor–stator cavities across three values of Φ

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Fig. 8

Unbladed double lip seal: normalized pressure, P¯, and seal effectiveness, εc, across two vane pitches in the rim seal and rotor–stator cavities across three values of Φ

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Fig. 9

Vane pressure field peak-to-peak pressures for the single lip and double lip seals bladed and unbladed at the high Re condition

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Fig. 10

Difference in εc across the single lip and double lip seals plotted against Φ and against cavity εc

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Fig. 11

Radial seal effectiveness profile in the rim seal cavity for the single lip seal

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Fig. 12

Unbladed configuration of single lip seal at the high Re condition: circumferential εc for three values of Φ labeled (a), (b), and (c) and eccentricity, e, measurements relative to seal clearance, sc

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Fig. 13

(a) Schematic representation of likely nonuniform ingestion pattern into the rotor–stator cavity. (b) Radial εc profiles at location a–a for unbladed single lip seal showing a radial increase in εc. (c) A radial increase in seal effectiveness from literature. Replotted from Sangan et al. [45]. (a) Hypothesized flow path along stator boundary layer, (b) radial εc measurements (section a–a), and (c) in literature.

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Fig. 14

Unbladed configuration of double lip seal at the high Re condition: circumferential εc ∼ 0.8

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Fig. 15

Spectrograms of the unsteady pressure in the rim seal cavity for the single lip seal with and without rotor blades at Reθ = 4.9 × 106 and Rex = 2.3 × 106. The spectrograms are plotted for three levels of cavity εc, a, b, c. Note: ΔPseal is taken at a cavity εc of 0.875.

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Fig. 16

Spectrograms of the unsteady pressure in the rim seal cavity for the double lip seal with and without rotor blades at Reθ = 4.9 × 106 and Rex = 2.3 × 106. The spectrograms are plotted for three levels of cavity εc, a, b, c. Note: ΔPseal is taken at a cavity εc of 0.925.

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Fig. 17

Single lip seal, bladed configuration at Reθ = 4.9 × 106, Rex = 2.3 × 106, and cavity εc ∼ 0.9: spectrograms of the unsteady pressure signal at three radial locations (rim seal, rotor–stator cavity, and purge feed cavity) over 60 disk revolutions

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Fig. 18

Comparison of steady and unsteady pressures for the single lip (a) and double lip (b) seals, Reθ = 4.9 × 106, Rex = 2.3 × 106

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Fig. 19

Single lip seal. Top: spectrograms of unsteady pressure signal in the rim seal cavity at the three disk speeds corresponding to a, b, and c. Bottom: variation in seal effectiveness, εc, with disk speed normalized by mainstream velocity at three radial locations.

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Fig. 20

Double lip seal. Top: spectrograms of unsteady pressure signal in the rim seal cavity at three disk speeds. Bottom: variation in seal effectiveness, εc, with disk speed normalized by mainstream velocity at three radial locations.

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Fig. 21

Effect of disk speed on relative flow velocity at the rim seal cavity

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