0
Research Papers: Gas Turbines: Turbomachinery

Numerical Characterization of Hot-Gas Ingestion Through Turbine Rim Seals

[+] Author and Article Information
Riccardo Da Soghe

Ergon Research s.r.l.,
Via Panciatichi 92,
Florence 50127, Italy
e-mail: riccardo.dasoghe@ergonresearch.it

Cosimo Bianchini

Ergon Research s.r.l.,
Via Panciatichi 92,
Florence 50127, Italy

Carl M. Sangan, James A. Scobie, Gary D. Lock

Department of Mechanical Engineering,
University of Bath,
Bath BA2 7AY, UK

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received June 28, 2016; final manuscript received July 28, 2016; published online October 11, 2016. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(3), 032602 (Oct 11, 2016) (9 pages) Paper No: GTP-16-1282; doi: 10.1115/1.4034540 History: Received June 28, 2016; Revised July 28, 2016

This paper deals with a numerical study aimed at the characterization of hot-gas ingestion through turbine rim seals. The numerical campaign focused on an experimental facility which models ingress through the rim seal into the upstream wheel-space of an axial-turbine stage. Single-clearance arrangements were considered in the form of axial- and radial-seal gap configurations. With the radial-seal clearance configuration, computational fluid dynamics (CFD) steady-state solutions were able to predict the system sealing effectiveness over a wide range of coolant mass flow rates reasonably well. The greater insight of flow field provided by the computations illustrates the thermal buffering effect when ingress occurs: For a given sealing flow rate, the effectiveness on the rotor was significantly higher than that on the stator due to the axial flow of hot gases from stator to rotor caused by pumping effects. The predicted effectiveness on the rotor was compared with a theoretical model for the thermal buffering effect showing good agreement. When the axial-seal clearance arrangement is considered, the agreement between CFD and experiments worsens; the variation of sealing effectiveness with coolant flow rate calculated by means of the simulations displays a distinct kink. It was found that the “kink phenomenon” can be ascribed to an overestimation of the egress spoiling effects due to turbulence modeling limitations. Despite some weaknesses in the numerical predictions, the paper shows that CFD can be used to characterize the sealing performance of axial- and radial-clearance turbine rim seals.

FIGURES IN THIS ARTICLE
<>
Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Owen, J. , and Rogers, R. H. , 1989, Flow and Heat Transfer in Rotating-Disc Systems, Volume 1—Rotor Stator Systems, Research Studies Press Ltd., Taunton, UK.
Sangan, C. M. , Pountney, O. J. , Zhou, K. , Wilson, M. , Owen, J. M. , and Lock, G. D. , 2013, “ Experimental Measurements of Ingestion Through Turbine Rim Seals—Part 1: Externally Induced Ingress,” ASME J. Turbomach., 135(2), p. 021012. [CrossRef]
Bayley, F. J. , and Owen, J. , 1970, “ Fluid Dynamics of a Shrouded Disk System With a Radial Outflow of Coolant,” ASME J. Eng. Power, 92(3), pp. 335–341. [CrossRef]
Chew, J. W. , 1991, “ A Theoretical Study of Ingress for Shrouded Rotating Disk Systems With Radial Outflow,” ASME J. Turbomach., 113(1), pp. 91–97. [CrossRef]
Chew, J. W. , Dadkhah, S. , and Turner, A. B. , 1992, “ Rim Sealing of Rotor–Stator Wheelspaces in the Absence of External Flow,” ASME J. Turbomach., 114(2), pp. 433–438. [CrossRef]
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]
Phadke, U. P. , and Owen, J. M. , 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. P. , and Owen, J. M. , 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]
Phadke, U. P. , and Owen, J. M. , 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]
Daniels, W. A. , Johnson, B. V. , Graber, D. J. , and Martin, R. J. , 1992, “ Rim Seal Experiments and Analysis for Turbine Applications,” ASME J. Turbomach., 114(2), pp. 426–432. [CrossRef]
Graber, D. J. , Daniels, W. A. , and Johnson, B. V. , 1987, “ Disk Pumping Test,” Report No. AFWAL -TR-87-2050. http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA187199
Scobie, J. A. , Sangan, C. M. , Owen, J. M. , and Lock, G. D. , 2016, “ Review of Ingress in Gas Turbines,” ASME J. Eng. Gas Turbines Power, 138(12), p. 120801. [CrossRef]
Sangan, C. M. , Scobie, J. A. , Zhou, K. , Wilson, M. , Owen, J. M. , and Lock, G. D. , 2014, “ Performance of a Finned Turbine Rim Seal,” ASME J. Turbomach., 136(11), p. 111008. [CrossRef]
Cho, G. H. , Sangan, C. M. , Owen, J. M. , and Lock, G. D. , 2015, “ Effect of Ingress on Turbine Discs,” ASME J. Eng. Gas Turbines Power, 138(4), p. 042502. [CrossRef]
Mear, L. I. , Owen, J. M. , and Lock, G. D. , 2015, “ Theoretical Model to Determine Effect of Ingress on Turbine Discs,” ASME J. Eng. Gas Turbines Power, 138(3), p. 032502. [CrossRef]
Sangan, C. M. , Pountney, O. J. , Zhou, K. , Wilson, M. , Owen, J. M. , and Lock, G. D. , 2011, “ Experimental Measurements of Ingestion Through Turbine Rim Seals—Part 2: Rotationally-Induced Ingress,” ASME Paper No. GT2011-45313.
Da Soghe, R. , Facchini, B. , Innocenti, L. , and Poncet, S. , 2010, “ Numerical Benchmark of Turbulence Modelling in Gas Turbine Rotor-Stator System,” ASME Paper No. GT2010-22627.
Poncet, S. , Nguyen, T. , Harmand, S. , Pell, J. , Da Soghe, R. , Bianchini, C. , and Viazzo, S. , 2013, “ Turbulent Impinging Jet Flow Into an Unshrouded Rotor-Stator System: Hydrodynamics and Heat Transfer,” Int. J. Heat Fluid Flow, 44, pp. 719–734. [CrossRef]
Hills, N. J. , Chew, J. W. , and Turner, A. B. , 2002, “ Computational and Mathematical Modeling of Turbine Rim Seal Ingestion,” ASME J. Turbomach., 124(2), pp. 306–315. [CrossRef]
Laskowski, G. M. , Bunker, R. S. , Bailey, J. , and Ledezma, G. , 2009, “ An Investigation of Turbine Wheelspace Cooling Flow Interaction With a Transonic Hot Gas Path Part 2: CFD Simulations,” ASME Paper No. GT2009-59193.
Andreini, A. , Da Soghe, R. , Facchini, B. , and Zecchi, S. , 2008, “ Turbine Stator Well CFD Studies: Effects of Cavity Cooling Air Flow,” ASME Paper No. GT2008-51067.
Cao, C. , Chew, J. , Millington, P. , and Hogg, S. , 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. , Funke, J. , and Decker, A. , 2004, “ Interaction of Rim Seal and Annulus Flows in an Axial Flow Turbine,” ASME Paper No. GT2004-53829.
Zhou, D. , Roy, R. , Wang, C. , and Glahn, J. , 2009, “ Main Gas Ingestion in a Turbine Stage for Three Rim Cavity Configurations,” ASME Paper No. GT2009-59851.
O'Mahoney, T. S. D. , Hills, N. J. , Chew, J. W. , and Scanlon, T. , 2010, “ Large-Eddy Simulations of Rim Seal Ingestion,” ASME Paper No. GT2010-22962.
Pountney, O. J. , Sangan, C. M. , Lock, G. D. , and Owen, J. M. , 2013, “ Effect of Ingestion on Temperature of Turbine Discs,” ASME J. Turbomach., 135(5), p. 051010. [CrossRef]
Zhou, K. , Wood, S. N. , and Owen, J. M. , 2013, “ Statistical and Theoretical Models of Ingestion Through Turbine Rim Seals,” ASME J. Turbomach., 135(2), p. 021014. [CrossRef]
Scobie, J. A. , Sangan, C. M. , Owen, J. , Wilson, M. , and Lock, G. D. , 2014, “ Experimental Measurements of Hot Gas Ingestion Through Turbine Rim Seals at Off-Design Conditions,” Proc. Inst. Mech. Eng., Part A, 228(5), pp. 491–507. [CrossRef]
Bianchini, C. , Andrei, L. , Andreini, A. , and Facchini, B. , 2013, “ Numerical Benchmark of Non-Conventional RANS Turbulence Models for Film and Effusion Cooling,” ASME J. Turbomach., 135(4), p. 041026. [CrossRef]
Holloway, D. S. , Walters, D. K. , and Leylek, J. H. , 2005, “ Computational Study of Jet-in-Crossflow and Film Cooling Using a New Unsteady-Based Turbulence Model,” ASME Paper No. GT2005-68155.
Savov, S. , Atkins, N. , and Uchida, S. , 2016, “ Comparison of Single and Double Lip Rim Seal Geometry,” ASME Paper No. GT2016-56317.

Figures

Grahic Jump Location
Fig. 1

Variation of static pressure in a turbine annulus. Radially inward arrows indicate hot-gas ingress and radially outward ones cooler egress, corresponding, respectively, to regions of higher and lower pressure than the wheel-space

Grahic Jump Location
Fig. 2

Simplified diagram of ingress and egress, showing boundary layers on the stator and rotor

Grahic Jump Location
Fig. 3

Rig test section (flow is from left to right)

Grahic Jump Location
Fig. 5

Numerical grid details

Grahic Jump Location
Fig. 6

Variation of effectiveness with nondimensional sealing flow rate for radial-clearance seal (colored symbols are computations, open symbols are experimental measurements made on the stator, and lines are theoretical curves from Eqs. (4) and (5))

Grahic Jump Location
Fig. 7

Effect of sealing flow rate on radial variation of effectiveness on the stator for the radial-clearance seal: computations (left) and measurements (right)

Grahic Jump Location
Fig. 8

Computed radial variation of effectiveness on stator and rotor surfaces for radial-clearance seal

Grahic Jump Location
Fig. 12

Sealing air concentration at low span, Φ0 = 0.253

Grahic Jump Location
Fig. 11

Velocity contour across the rim: Φ0 = 0 (up) and Φ0 = 0.253 (down)

Grahic Jump Location
Fig. 10

Distribution of Cp over nondimensional vane pitch and ΔCp0.5 for different Φ0 values (colored symbols are computations, and open symbols are experimental measurements)

Grahic Jump Location
Fig. 9

Variation of effectiveness with nondimensional sealing flow rate for axial-clearance seal (colored symbols are computations, and open symbols are experimental measurements)

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