0
Research Papers

Analysis of the Unsteady Overtip Casing Heat Transfer in a High Speed Turbine

[+] Author and Article Information
S. Lavagnoli

e-mail: lavagnoli@vki.ac.be

G. Paniagua

e-mail: paniagua@vki.ac.be

C. De Maesschalck

e-mail: demaess@vki.ac.be

T. Yasa

e-mail: yasa@vki.ac.be
von Karman Institute for Fluid Dynamics,
Rhode-Saint-Genèse, Belgium

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received July 4, 2012; final manuscript received August 8, 2012; published online March 25, 2013. Editor: David Wisler.

J. Turbomach 135(3), 031027 (Mar 25, 2013) (12 pages) Paper No: TURBO-12-1126; doi: 10.1115/1.4007509 History: Received July 04, 2012; Revised August 08, 2012

In modern gas turbine engines, the rotor casing is vulnerable to thermal failures due to large unsteady heat fluxes. The rotor tip flow unsteadiness is induced by the periodic passage of the rotor blades, with an intensity dependent on the tip gap geometry. Hence, the understanding of the physics is of paramount importance to develop appropriate predictive tools and improve the cooling schemes. The present research aims at providing essential information on the flow conditions, which should serve to assess the relative impact of the overtip flow, tip gap magnitude, and work extraction processes on the casing thermal load. This paper presents simultaneous measurements of steady and unsteady heat transfer, pressure and rotor tip clearance in the casing of a transonic turbine stage. The research article was tested in a compression tube facility operating at engine representative conditions (vane Mach number 1.07, vane outlet Reynolds number 1.3 × 106, pressure ratio is 2.92, at 6790 rpm). The rotor blade geometry has a flat tip with a nominal tip clearance of about 0.4% of blade height. The heat transfer, pressure, and tip clearance data were obtained at three circumferential positions around the turbine casing. The heat flux was monitored using a single-layered thin film gauge able to resolve with high fidelity the wall temperature fluctuations. The heat flux sensor was mounted on a probe equipped with a heating device that allows varying the wall temperature. A series of experiments was performed at different heating rates to derive the local adiabatic wall temperature and the adiabatic convective heat transfer coefficient. A high bandwidth capacitive sensor provided the instantaneous value of the single blade tip clearance. A simple zero-dimensional model has been proved effective to predict the local flow temperature while the rotor spins up prior to the test, and estimate the overtip flow temperature during a test.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Glezer, B., 2004, “Thermal-Mechanical Design Factors Affecting Turbine Blade Tip Clearance” Turbine Blade Tip Design and Tip Clearance Treatment (von Karman Institute for Fluid Dynamics Lecture Series), T.Arts, ed., von Karman Institute for Fluid Dynamics, Rhode-St-Genèse, Belgium.
Chyu, M. K., 2001, “Heat Transfer Near Turbine Nozzle Endwall,” Ann. NY Acad. Sci., 934, pp. 27–36. [CrossRef]
Malak, M., Liu, J., and Zurmehly, E., 2011, “Turbine Shroud Durability Analysis Using Time Unsteady CFD and Si-C Testing,” ISABE Paper No. 2011-1706.
Bunker, R. S., 2001, “A Review of Turbine Blade Tip Heat Transfer in Gas Turbine Systems,” Ann. N.Y. Acad. Sci., 934, pp. 64–79. [CrossRef] [PubMed]
Moore, J., Moore, J. G., Henry, G. S., and Chaudhry, U., 1989, “Flow and Heat Transfer In Turbine Tip Gaps,” ASME J. Turbomach., 111, pp. 301–309. [CrossRef]
Moore, J., and Elward, K. M., 1993, “Shock Formation in Overexpanded Tip Leakage Flow,” ASME J. Turbomach., 115, pp. 392–399. [CrossRef]
Wheeler, A. P. S., Atkins, N. R., and He, L., 2009, “Turbine Blade Tip Heat Transfer in Low Speed And High Speed Flows,” ASME J. Turbomach., 133, pp. 041025. [CrossRef]
Shyam, V., Ameri, A., and Chen, J.-P., 2012, “Analysis Of Unsteady Tip and Endwall Heat Transfer in A Highly Loaded Transonic Turbine Stage,” ASME J. Turbomach., 134(4), p. 041022. [CrossRef]
Newton, P. J., Lock, G. D., Krishnababu, S. K., Hodson, H. P., Dawes, W. N., Hannis, J., and Whitney, C., 2006, “Heat Transfer and Aerodynamics of Turbine Blade Tips in A Linear Cascade,” ASME J. Turbomach., 128(2), pp. 300–309. [CrossRef]
Zhang, Q., O'Dowd, D. O., He, L., Wheeler, A. P. S., Ligrani, P. M., and Cheong, B. C. Y., 2011, “Overtip Shock Wave Structure and Its Impact on Turbine Blade Tip Heat Transfer,” ASME J. Turbomach., 133(4), p. 041001. [CrossRef]
Krishnababu, S. K., Dawes, W. N., Hodson, H. P., Lock, G. D., Hannis, J., and Whitney, C., 2009, “Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part II: Effect of Relative Casing Motion,” ASME J. Turbomach., 131(1), p. 011007. [CrossRef]
Zhang, Q., O'Dowd, D. O., He, L., Oldfield, M. L. G., and Ligrani, P. M., 2011, “Transonic Turbine Blade Tip Aerothermal Performance With Different Tip Gaps—Part I: Tip Heat Transfer,” ASME J. Turbomach., 133(4), p. 041027. [CrossRef]
Guenette, G. R., Epstein, A. H., Norton, R. J., and Yuhzang, C., 1985, “Time Resolved Measurements of a Turbine Rotor Stationary Tip Casing Pressure and Heat Transfer Field,” AIAA Paper No. 85-1220. [CrossRef]
Metzger, D. E., Dunn, M. G., and Hah, C., 1991, “Turbine Tip and Shroud Heat Transfer,” ASME J. Turbomach., 113(3), pp. 502–507. [CrossRef]
Thorpe, S. J., Miller, R. J., Yoshino, S., Ainsworth, R. W., and Harvey, N. W., 2007, “The Effect of Work Processes on the Casing Heat Transfer of a Transonic Turbine,” ASME J. Turbomach., 129(1), pp. 84–91. [CrossRef]
Thorpe, S. J., and Ainsworth, R. W., 2008, “The Effects of Blade Passing on the Heat Transfer Coefficient of the Overtip Casing in a Transonic Turbine Stage,” ASME J. Turbomach., 130(4), p. 041009. [CrossRef]
Thorpe, S., Yoshino, S., Ainsworth, R., and Harvey, N., 2004, “An Investigation of the Heat Transfer and Static Pressure on the Casing Wall of an Axial Turbine Operating At Engine Representative Flow Conditions (I): Time-Mean Results,” Int. J. Heat Fluid Flow, 25(6), pp. 933–944. [CrossRef]
Thorpe, S., Yoshino, S., Ainsworth, R., and Harvey, N., 2004, “An Investigation of the Heat Transfer and Static Pressure on the Casing Wall of an Axial Turbine Operating At Engine Representative Flow Conditions (II): Time-Resolved Results,” Int. J. Heat Fluid Flow, 25(6), pp. 945–960. [CrossRef]
Krishnababu, S. K., Newton, P. J., Dawes, W. N., Lock, G. D., Hodson, H. P., Hannis, J., and Whitney, C., 2009, “Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part I: Effect of Tip Geometry and Tip Clearance Gap,” ASME J. Turbomach., 131(1), p. 011006. [CrossRef]
Chana, K. S., and Jones, T. V., 2003, “An Investigation on Turbine Tip and Shroud Heat Transfer,” ASME J. Turbomach., 125(3), pp. 513–520. [CrossRef]
Schultz, D. L., and Jones, T. V., 1973, “Heat Transfer Measurements in Short Duration Hypersonic Facilities,” Paper No. AGARD AG-165.
Lavagnoli, S., Paniagua, G., Tulkens, M., and Steiner, A., 2011, “High-Fidelity Rotor Gap Measurements in a Short-Duration Turbine Rig,” Mech. Syst. Signal Process., Vol. 27, pp. 590–603. [CrossRef]
Dénos, R., 1996, “Aero-Thermodynamic Investigation of the Unsteady Flow in a Transonic Turbine Rotor,” Ph.D. thesis, von Karman Institute for Fluid Dynamics/University of Poitiers, Rhode-St-Genèse Belgium.
Solano, J. P., and Paniagua, G., 2009, “Novel Two-Dimensional Transient Heat Conduction Calculation in a Cooled Rotor: Ventilation Preheating—Blow-Down Flux,” ASME J. Heat Transfer, 131(8), pp. 1–9. [CrossRef]
Thomas, G. A., Atkins, N. R., Thorpe, S. J., Ainsworth, R. W., and Harvey, N. W., 2007, “The Effect of a Casing Step on the Over-Tip Aerothermodynamics of a Transonic HP Turbine Stage,” ASME Paper No. GT2007-27780. [CrossRef]
Thorpe, S. J., Yoshino, S., Ainsworth, R. W., and Harvey, N. W., 2004, “Improved Fast-Response Heat Transfer Instrumentation for Short-Duration Wind Tunnels,” Meas. Sci. Technol., 15(9), pp. 1897–1909. [CrossRef]
Polanka, M. D., Clark, J. P., White, A. L., Meininger, M., and Praisner, T. J., 2003, “Turbine Tip and Shroud Heat Transfer and Loading: Part B—Comparisons Between Prediction and Experiment Including Unsteady Effects,” ASME Paper No. GT2003-38916. [CrossRef]
Harvey, N. W., 2004, “Aero-Thermal Implications of Shroudless and Shrouded Blades,” Turbine Blade Tip Design and Tip Clearance Treatment (von Karman Institute for Fluid Dynamics Lecture Series), T.Arts, ed., von Karman Institute for Fluid Dynamics, Rhode-St-Genèse, Belgium.
Zhang, Q., and He, He, 2011, “Overtip Choking and Its Implications on Turbine Blade-Tip Aerodynamics Performance,” J. Propul. Power, 0748–4658, 27, no. 5 pp. 1008–1014 [CrossRef].

Figures

Grahic Jump Location
Fig. 1

3D view of the turbine stage (left), rotor blade with flat tip (right)

Grahic Jump Location
Fig. 2

Compression tube facility overview (left), change of conditions in a typical test (right)

Grahic Jump Location
Fig. 3

Experimental and predicted tip clearance envelope during turbine test rig operation

Grahic Jump Location
Fig. 4

Blade-to-blade radius variation from the longest blade in static and running conditions

Grahic Jump Location
Fig. 5

Installation of the casing instrumentation on the turbine rig (a) circumferential locations of the instrumented probe (b) meridional view of the turbine test section (c) axial location of the probe

Grahic Jump Location
Fig. 6

Heat transfer probe design and instrumented ceramic insert

Grahic Jump Location
Fig. 7

(a) Cut view of the fast-response pressure probe (b) tip clearance measurement system and its installation on the rotor casing

Grahic Jump Location
Fig. 8

Procedure for heat transfer and adiabatic wall temperature data reduction

Grahic Jump Location
Fig. 9

Measured casing wall time-resolved adiabatic wall temperature, Nusselt number, and static pressure as a function of rotor phase

Grahic Jump Location
Fig. 10

Adiabatic wall temperature, Nusselt number, and static pressure correlation with the blade-to-blade tip clearance

Grahic Jump Location
Fig. 11

Blade-to-blade signature of adiabatic wall temperature, Nusselt number, static pressure, and tip clearance for a blow-down experiment (left) and for a run-up (right)

Grahic Jump Location
Fig. 12

Adiabatic wall temperature correlation with the rotor speed

Grahic Jump Location
Fig. 13

Model of the flow work process on the rotor tip for a run-up test and a blow-down

Grahic Jump Location
Fig. 14

Predicted leakage flow absolute total temperature variations for a range of Mach numbers and flow angles, temperature variations sensitivity to change in tip leakage flow angle at different Mach numbers

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