0
Research Papers

The Aerothermal Performance of a Cooled Winglet Tip in a High Pressure Turbine Cascade

[+] Author and Article Information
Chao Zhou

State Key Laboratory for Turbulence and Complex Systems,
College of Engineering,
Peking University,
Beijing, 100871, China
e-mail: czhou@pku.edu.cn

Howard Hodson

Whittle Laboratory,
Department of Engineering,
University of Cambridge,
Cambridge, CB3 0FY, UK

Mark Stokes

Rolls-Royce plc,
Derby, DE24 8BJ, UK

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received November 12, 2011; final manuscript received November 29, 2011; published online March 25, 2013. Editor: David Wilser.

J. Turbomach 135(3), 031005 (Mar 25, 2013) (10 pages) Paper No: TURBO-11-1242; doi: 10.1115/1.4006611 History: Received November 12, 2011; Revised November 29, 2011

The aerothermal performance of a winglet tip with cooling holes on the tip and on the blade surface near the tip is reported in this paper. The investigation was based on a high pressure turbine cascade. Experimental and numerical methods were used. The effects of the coolant mass flow rate are also studied. Because the coolant injection partially blocks the tip leakage flow, more passage flow is turned by the blade. As a result, the coolant injection on the winglet tip reduces the deviation of the flow downstream of the cascade due to the tip leakage flow. However, the tip leakage loss increases slightly with the coolant mass flow ratio. Both the computational fluid dynamics tools and experiments using the Amonia–Diazo technique were used to determine the cooling effectiveness. On the blade pressure side surface, low cooling effectiveness appears around the holes due to the lack of the coolant from the cooling hole or the lift-off of the coolant from the blade surface when the coolant mass flow is high. The cooling effectiveness on the winglet tip is a combined effect of the coolant ejected from all the holes. On the top of the winglet tip, the average cooling effectiveness increases and the heat load decreases with increasing coolant mass flow. Due to its large area, the cooled winglet tip has a higher heat load than an uncooled flat tip at engine representative coolant mass flow ratio. Nevertheless, the heat flux rate per unit area of the winglet is much lower than that of an uncooled flat tip. The cycle analysis is carried out and the effects of relative tip-to-casing endwall motion are address.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Schabowski, Z., Hodson, H., Giacche, D., and Power, B., 2010, “Aeromechanical Optimisation of a Winglet-Squealer Tip for an Axial Turbine,” ASME Paper No. GT2010-23542. [CrossRef]
Yaras, M. I., and Sjolander, S. A., 1991, “Measurements of the Effects of Winglets on Tip-Leakage Losses in a Linear Turbine Cascade,” ASME Paper No. ISABE 91-7011.
Liu, H. C., Booth, T. C., and Tall, W. A., 1979, “An Application of 3-D Viscous Flow Analysis to the Design of a Low-Aspect-Ratio Turbine,” ASME Paper No. 79-GT-53.
Harvey, N. W., 2004, “Turbine Blade Tip Design and Tip Clearance Treatment,” VKI Lecture Series VKI-LS 2004-02, Brussels, January 19–23.
Dey, D., and Camci, C., 2001, “Aerodynamic Tip Desensitization of an Axial Turbine Rotor Using Tip Platform Extensions,” ASME Paper No. 2001-GT-0484.
Harvey, N., Newman, D., and Haselbach, F., 2006, “An Investigation Into a Novel Turbine Rotor Winglet: Part I—Design and Model Rig Test Results,” ASME Paper No. GT2006-90456. [CrossRef]
Papa, M., Glodstein, R. J., and Gori, F., 2003, “Effects of Tip Geometry and Tip Clearance on the Mass/Heat Transfer From a Large-Scale Gas Turbine Blade,” ASME J. Turbomach., 125, pp. 90–96. [CrossRef]
O’Dowd, D., Zhang, Q., He, L., Oldfield, M., Ligrani, P., Cheong, B., and Tibbott, I., 2010, “Aero-Thermal Performance of a Winglet at Engine Representative Mach and Reynolds Numbers,” ASME Paper No. GT2010-22794. [CrossRef]
Hohlfeld, E. M., Christophel, J. R., Couch, E. L., and Thole, K. A., 2003, “Predictions of Cooling From Dirt Purge Holes Along the Tip of a Turbine Blade,” ASME Paper No. GT2003-38251. [CrossRef]
Zhou, C., and Hodson, H., 2009, “The Tip Leakage Flow of an Unshrouded High Pressure Turbine Blade With Tip Cooling,” ASME Paper No. GT2009-59637. [CrossRef]
Hofer, T., Legrand, M., Pons, L., and Arts, T., 2009, “Aerodynamic Investigation of the Leakage Flow For a Blade With a Squealer Tip at Transonic Condition,” 8th European Turbomachinery Conference, Graz, Austria, March 23–27.
Hofer, T., and Arts, T., 2009, “Aerodynamic Investigation of the Tip Leakage Flow for Blades With Different Tip Squealer Geometries at Transonic Conditions,” ASME Paper No. GT2009-59909. [CrossRef]
Kim, Y. W., and Metzger, D. E., 1995b, “Heat Transfer and Effectiveness on Film Cooled Turbine Blade Tip Models,” ASME J. Turbomach., 117, pp. 12–21. [CrossRef]
Newton, P. J., Lock, G. D., Krishnababu, S. K., Hodson, H. P., Dawes, W. N., Hannis, J., and Whitney, C., 2007, “Aero-Thermal Investigation of Tip Leakage Flow in Axial Flow Turbines: Part III—Film Cooling,” ASME Paper No. GT-2007-27368. [CrossRef]
Christophel, J. R., Thole, K. A., and Cunha, F. J., 2005, “Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part I: Adiabatic Effectiveness Measurements,” ASME J. Turbomach., 127, pp. 270–277. [CrossRef]
Christophel, J. R., Thole, K. A., and Cunha, F. J., 2005, “Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part II: Heat Transfer Measurements,” ASME J. Turbomach., 127, pp. 278–286. [CrossRef]
Ahn, J., Mhertras, S., and Han, J. C., 2005, “Film-Cooling Effectiveness on a Gas Turbine Blade Tip Using Pressure-Sensitive Paint,” ASME J. Turbomach., 127, pp. 521–530. [CrossRef]
Zhang, Q., O’Dowd, D, He, L., Oldfield, M., and Ligrani, P., 2011, “Transonic Turbine Blade Tip Aerothermal Performance With Different Tip Gaps—Part I: Tip Heat Transfer,” ASME J. Turbomach., 133, pp. 041027–041035. [CrossRef]
Zhang, Q., O’Dowd, D, He, L., Wheeler, A. P. S., Ligrani, P., and Cheong, B., 2011, “Overtip Shock Wave Structure and Its Impact on Turbine Blade Heat Transfer,” ASME J. Turbomach., 133, pp. 041001–041009. [CrossRef]
O’Dowd, D., Zhang, Q., Ligrani, P., He, L., and Friedrichs, S., 2009, “Comparison of Heat Transfer Measurement Techniques on a Transonic Turbine Blade Tip,” ASME Paper No. GT2009-59376. [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 Paper No. GT2009-59404. [CrossRef]
Key, N., and Arts, T., 2006, “Comparison of Turbine Tip Leakage Flow for Flat Tip and Squealer Tip Geometries at High-Speed Conditions,” ASME J. Turbomach., 128, pp. 213–220. [CrossRef]
Chen, G., Dawes, W. N., and Hodson, H. P., 1993, “Numerical Analysis of Tip Gap Flow,” AIAA-93-2253, AIAA/SAE/ASME/ASEE 29th Joint Propulsion Conference & Exhibit Monterey, CA, June 28–30.
Friedrichs, S., Hodson, H., and Dawes, W. N., 1996, “Distribution of Film-Cooling Effectiveness on a Turbine Endwall Measured Using the Ammonia and Diazo Technique,” ASME J. Turbomach., 118, pp. 613–621. [CrossRef]
Shadid, J. N., and Eckert, E. R. G., 1991, “The Mass Transfer Analogy to Heat Transfer in Fluids With Temperature-Dependent Properties,” ASME J. Turbomach., pp. 27–33. [CrossRef]
Zhou, C., and Hodson, H., 2009, “The Aerodynamic Performance of the Tip Leakage Flow With Different Tip Geometries,” Proceedings of the 8th European Turbomachinery Conference, Graz, Austria, March 23–27, pp. 1469–1481.
Zhou, C., and Hodson, H., 2009, “Numerical Investigation of Thermal Performance of Unshrouded HP Turbine Blade Tips,” Int. J. Turbo Jet Engines, 26, pp. 227–284. [CrossRef]
Dey, D., 2001, “Tip Desensitization in an Axial Flow Turbine,” Ph.D. thesis, The Pennsylvania State University, University Park, PA.
Rao, N., and Camci, C., 2004a, “Axial Flow Turbine Tip Desensitization by Injection From a Tip Trench: Part 1—Effect of Injection Mass Flow Rate,” ASME Paper No. GT2004-53256. [CrossRef]
Kurzke, J., “Design and Off-Design Performance of Gas Turbines,” 2007, Gasturb 11 Manual, Germany.
Zhou, C., Hodson, H., Tibbott, I., and Stokes, M., “Effects of Endwall Motion on the Aero-Thermal Performance of a Winglet Tip in a HP Turbine,” ASME Paper No. GT2011-46373. [CrossRef]

Figures

Grahic Jump Location
Fig. 2

Geometry of cooled winglet tip

Grahic Jump Location
Fig. 3

Mesh of cooled winglet tip, τ = 1.9% C

Grahic Jump Location
Fig. 4

Midspan Cp distribution, CFD

Grahic Jump Location
Fig. 5

Cp of internal cooling configuration, Mc,ER, τ = 1.9%C, CFD

Grahic Jump Location
Fig. 6

Effects of coolant to flow field, τ = 1.9% C, 45% axial chord downstream cascade, exp

Grahic Jump Location
Fig. 7

Tip leakage loss of cooled tip, τ = 1.9% C

Grahic Jump Location
Fig. 8

Cooling effectiveness of cooled winglet tip, Mc,ER, τ = 1.9% C

Grahic Jump Location
Fig. 9

Effects of coolant on blade surface, Mc,ER, CFD

Grahic Jump Location
Fig. 10

Cooling effectiveness of cooled winglet tip, Mc,ER, τ = 1.9% C, CFD

Grahic Jump Location
Fig. 11

cooling effectiveness of blade suction side, Mc,ER, τ = 1.9% C, CFD

Grahic Jump Location
Fig. 12

Nusselt number of cooled winglet tip, Mc,ER, τ = 1.9% C, CFD

Grahic Jump Location
Fig. 13

Effects of coolant mass flow ratio—cooling effectiveness, pressure side surface, τ = 1.9% C, CFD

Grahic Jump Location
Fig. 14

Effects of coolant mass flow rate—cooling effectiveness, winglet tip, τ = 1.9% C, CFD

Grahic Jump Location
Fig. 15

Effects of coolant mass flow ratio on thermal performance of cooled winglet tip, τ = 1.9% C, CFD

Grahic Jump Location
Fig. 16

Effects of coolant mass flow ratio on engine core efficiency

Grahic Jump Location
Fig. 17

Effects of endwall motion on the cooling effectiveness of winglet tip, CFD

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