0
Research Papers: Gas Turbines: Structures and Dynamics

Cooling Injection Effect on a Transonic Squealer Tip—Part I: Experimental Heat Transfer Results and CFD Validation

[+] Author and Article Information
H. Ma

University of Michigan-Shanghai
Jiao Tong University Joint Institute,
Shanghai 200240, China
e-mail: haitengma@gmail.com

Q. Zhang

Department of Mechanical Engineering
and Aeronautics,
School of Engineering
and Mathematical Sciences,
City, University of London,
Northampton Square,
London EC1V 0HB, UK
e-mail: Qiang.Zhang.1@city.ac.uk

L. He

Department of Engineering Science,
University of Oxford,
Oxford OX2 0ES, UK
e-mail: Li.He@eng.ox.ac.uk

Z. Wang

University of Michigan-Shanghai
Jiao Tong University Joint Institute,
Shanghai 200240, China
e-mail: wangzhaoguang1991@hotmail.com

L. Wang

University of Michigan-Shanghai
Jiao Tong University Joint Institute,
Shanghai 200240, China
e-mail: lipo.wang@sjtu.edu.cn

1Corresponding author.

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 14, 2016; final manuscript received October 8, 2016; published online January 10, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(5), 052506 (Jan 10, 2017) (9 pages) Paper No: GTP-16-1338; doi: 10.1115/1.4035175 History: Received July 14, 2016; Revised October 08, 2016

Recent studies have demonstrated that the aerothermal characteristics of turbine rotor blade tip under a transonic condition are qualitatively different from those under a low-speed subsonic condition. The cooling injection adds further complexity to the over-tip-leakage (OTL) transonic flow behavior and aerothermal performance, particularly for commonly studied shroudless tip configurations such as a squealer tip. However there has been no published experimental study of a cooled transonic squealer. The present study investigates the effect of cooling injection on a transonic squealer through a closely combined experimental and CFD effort. Part I of this two-part paper presents the first of the kind tip cooling experimental data obtained in a transonic linear cascade environment (exit Mach number 0.95). Transient thermal measurements are carried out for an uncooled squealer tip and six cooling configurations with different locations and numbers of discrete holes. High-resolution distributions of heat transfer coefficient and cooling effectiveness are obtained. ansysFluent is employed to perform numerical simulations for all the experimental cases. The mesh and turbulence modeling dependence is first evaluated before further computational studies are carried out. Both the experimental and computational results consistently illustrate strong interactions between the OTL flow and cooling injection. When the cooling injection (even with a relatively small amount) is introduced, distinctive series of stripes in surface heat transfer coefficient are observed with an opposite trend in the chordwise variations on the squealer cavity floor and on the suction surface rim. Both experimental and CFD results have also consistently shown interesting signatures of the strong OTL flow–cooling interactions in terms of the net heat flux reduction distribution in areas seemingly unreachable by the coolant. Further examinations and analyses of the related flow physics and underlining vortical flow structures will be presented in Part II.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Bunker, R. S. , 2001, “ A Review of Turbine Blade Tip Heat Transfer,” Ann. N. Y. Acad. Sci., 934(1), pp. 64–79. [CrossRef] [PubMed]
Mayle, R. , and Metzger, D. , 1982, “ Heat Transfer at the Tip of an Unshrouded Turbine Blade,” 7th International Conference on Heat Transfer, Vol. 3, pp. 87–92. http://adsabs.harvard.edu/abs/1982hetr....3...87M
Bunker, R. S. , Bailey, J. C. , and Ameri, A. A. , 2000, “ Heat Transfer and Flow on the First-Stage Blade Tip of a Power Generation Gas Turbine—Part I: Experimental Results,” ASME J. Turbomach., 122(2), pp. 263–271. [CrossRef]
Ameri, A. A. , and Bunker, R. , 2000, “ Heat Transfer and Flow on the First-Stage Blade Tip of a Power Generation Gas Turbine—Part II: Simulation Results,” ASME J. Turbomach., 122(2), pp. 272–277. [CrossRef]
Newton, P. , Lock, G. , Krishnababu, S. , Hodson, H. , Dawes, W. , 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]
Krishnababu, S. , Newton, P. , Dawes, W. , Lock, G. D. , Hodson, H. , 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]
Metzger, D. , Bunker, R. , and Chyu, M. , 1989, “ Cavity Heat Transfer on a Transverse Grooved Wall in a Narrow Flow Channel,” ASME J. Heat Transfer, 111(1), pp. 73–79. [CrossRef]
Chyu, M. , Moon, H. , and Metzger, D. , 1989, “ Heat Transfer in the Tip Region of Grooved Turbine Blades,” ASME J. Turbomach., 111(2), pp. 131–138. [CrossRef]
Bunker, R. S. , and Bailey, J. C. , 2001, “ Effect of Squealer Cavity Depth and Oxidation on Turbine Blade Tip Heat Transfer,” ASME Paper No. GT2000-0155.
Azad, G. S. , Han, J.-C. , and Boyle, R. J. , 2000, “ Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade,” ASME J. Turbomach., 122(4), pp. 725–732. [CrossRef]
Azad, G. S. , Han, J.-C. , Bunker, R. S. , and Lee, C. P. , 2002, “ Effect of Squealer Geometry Arrangement on a Gas Turbine Blade Tip Heat Transfer,” ASME J. Heat Transfer, 124(3), pp. 452–459. [CrossRef]
Kwak, J. S. , Ahn, J. , Han, J. C. , Lee, C. P. , Bunker, R. S. , Boyle, R. , and Gaugler, R. , 2003, “ Heat Transfer Coefficients on the Squealer Tip and Near-Tip Regions of a Gas Turbine Blade With Single or Double Squealer,” ASME J. Turbomach., 125(4), pp. 778–787. [CrossRef]
Zhou, C. , and Hodson, H. , 2012, “ Squealer Geometry Effects on Aerothermal Performance of Tip-Leakage Flow of Cavity Tips,” J. Propul. Power, 28(3), pp. 556–567. [CrossRef]
Bunker, R. S. , 2006, “ Axial Turbine Blade Tips: Function, Design, and Durability,” J. Propul. Power, 22(2), pp. 271–285. [CrossRef]
Kwak, J. S. , and Han, J. C. , 2003, “ Heat Transfer Coefficients and Film-Cooling Effectiveness on a Gas Turbine Blade Tip,” ASME J. Heat Transfer, 125(3), pp. 494–502. [CrossRef]
Christophel, J. R. , and Thole, K. A. , 2005, “ Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part I: Adiabatic Effectiveness Measurements,” ASME J. Turbomach., 127(2), 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(2), pp. 278–286. [CrossRef]
Newton, P. , Lock, G. D. , Krishnababu, S. , Hodson, H. , Dawes, W. , Hannis, J. , and Whitney, C. , 2009, “ Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part III: Tip Cooling,” ASME J. Turbomach., 131(1), p. 011008. [CrossRef]
Kwak, J. S. , and Han, J. C. , 2003, “ Heat Transfer Coefficients and Film Cooling Effectiveness on the Squealer Tip of a Gas Turbine Blade,” ASME J. Turbomach., 125(4), pp. 648–657. [CrossRef]
Ahn, J. , Mhetras, S. , and Han, J.-C. , 2005, “ Film-Cooling Effectiveness on a Gas Turbine Blade Tip Using Pressure-Sensitive Paint,” ASME J. Heat Transfer, 127(5), pp. 521–530. [CrossRef]
Mhetras, S. , Narzary, D. , Gao, Z. , and Han, J.-C. , 2008, “ Effect of a Cutback Squealer and Cavity Depth on Film-Cooling Effectiveness on a Gas Turbine Blade Tip,” ASME J. Turbomach., 130(2), p. 021002. [CrossRef]
Naik, S. , Georgakis, C. , Hofer, T. , and Lengani, D. , 2012, “ Heat Transfer and Film Cooling of Blade Tips and Endwalls,” ASME J. Turbomach., 134(4), p. 041004. [CrossRef]
Wheeler, A. P. , Atkins, N. R. , and He, L. , 2011, “ Turbine Blade Tip Heat Transfer in Low Speed and High Speed Flows,” ASME J. Turbomach., 133(4), p. 041025. [CrossRef]
Zhang, Q. , He, L. , Wheeler, A. , Ligrani, P. , and Cheong, B. , 2011, “ Overtip Shock Wave Structure and Its Impact on Turbine Blade Tip Heat Transfer,” ASME J. Turbomach., 133(4), p. 041001. [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(4), p. 041027. [CrossRef]
Zhang, Q. , and He, L. , 2011, “ Overtip Choking and Its Implications on Turbine Blade-Tip Aerodynamic Performance,” J. Propul. Power, 27(5), pp. 1008–1014. [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]
Zhang, Q. , and He, L. , 2014, “ Impact of Wall Temperature on Turbine Blade Tip Aerothermal Performance,” ASME J. Eng. Gas Turbines Power, 136(5), p. 052602. [CrossRef]
O'Dowd, D. , Zhang, Q. , He, L. , Oldfield, M. , Ligrani, P. , Cheong, B. , and Tibbott, I. , 2011, “ Aerothermal Performance of a Winglet at Engine Representative Mach and Reynolds Numbers,” ASME J. Turbomach., 133(4), p. 041026. [CrossRef]
Anto, K. , Xue, S. , Ng, W. , Zhang, L. , and Moon, H. , 2013, “ Effects of Tip Clearance Gap and Exit Mach Number on Turbine Blade Tip and Near-Tip Heat Transfer,” ASME Paper No. GT2013-94345.
Dunn, M. , and Haldeman, C. , 2000, “ Time-Averaged Heat Flux for a Recessed Tip, Lip, and Platform of a Transonic Turbine Blade,” ASME J. Turbomach., 122(4), pp. 692–698. [CrossRef]
Key, N. L. , 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(2), pp. 213–220. [CrossRef]
Virdi, A. , Zhang, Q. , He, L. , Li, H. , and Hunsley, R. , 2015, “ Aerothermal Performance of Shroudless Turbine Blade Tips With Relative Casing Movement Effects,” J. Propul. Power, 31(2), pp. 527–536. [CrossRef]
O'Dowd, D. , Zhang, Q. , He, L. , Cheong, B. , and Tibbott, I. , 2013, “ Aerothermal Performance of a Cooled Winglet at Engine Representative Mach and Reynolds Numbers,” ASME J. Turbomach., 135(1), p. 011041. [CrossRef]
Wheeler, A. P. , and Saleh, Z. , 2013, “ Effect of Cooling Injection on Transonic Tip Flows,” J. Propul. Power, 29(6), pp. 1374–1381. [CrossRef]
Wang, Z. , Zhang, Q. , Liu, Y. , and He, L. , 2015, “ Impact of Cooling Injection on the Transonic Over-Tip Leakage Flow and Squealer Aerothermal Design Optimization,” ASME J. Eng. Gas Turbines Power, 137(6), p. 062603. [CrossRef]
Zhou, C. , 2015, “ Thermal Performance of Transonic Cooled Tips in a Turbine Cascade,” J. Propul. Power, 31(5), pp. 1–13. [CrossRef]
Ma, H. , Zhang, Q. , He, L. , Wang, Z. , and Wang, L. , 2016, “ Cooling Injection Effect on a Transonic Squealer Tip—Part 2: Analysis of Aerothermal Interaction Physics,” ASME Paper No. GT2016-57587.
Zheng, R. , Li, M. , Wang, Z. , and Zhang, Q. , 2015, “ Control of Blow-Down Wind Tunnel Using Combined Extended and Nonlinear Predictive Filters,” ASME Paper No. GT2015-42908.
Xi, J. , Zhang, Q. , Li, M. , and Wang, Z. , 2013, “ Advanced Flow Control for Supersonic Blowdown Wind Tunnel Using Extended Kalman Filter,” ASME Paper No. GT2013-95281.
Ma, H. , Wang, Z. , Wang, L. , Zhang, Q. , Yang, Z. , and Bao, Y. , 2015, “ Ramp Heating in High-Speed Transient Thermal Measurement With Reduced Uncertainty,” ASME Paper No. GT2015-43012.
Evans, R. , Dawes, W. , and Zhang, Q. , 2013, “ Application of Design of Experiment to a Gas Turbine Cascade Test Cell,” ASME Paper No. GT2013-94314.
Chen, W. , 2013, “ Improvements on Conventional Transient Thermal Measurement on Turbine Blade,” M.S. thesis, Shanghai Jiao Tong University, Shanghai, China.
Mee, D. , Chiu, H. , and Ireland, P. , 2002, “ Techniques for Detailed Heat Transfer Measurements in Cold Supersonic Blowdown Tunnels Using Thermochromic Liquid Crystals,” Int. J. Heat Mass Transfer, 45(16), pp. 3287–3297. [CrossRef]
Kays, W. M. , Crawford, M. E. , and Weigand, B. , 2012, Convective Heat and Mass Transfer, McGraw-Hill, New York.
Oldfield, M. L. G. , 2008, “ Impulse Response Processing of Transient Heat Transfer Gauge Signals,” ASME J. Turbomach., 130(2), pp. 1–9. [CrossRef]
O'Dowd, D. O. , Zhang, Q. , He, L. , Ligrani, P. M. , and Friedrichs, S. , 2011, “ Comparison of Heat Transfer Measurement Techniques on a Transonic Turbine Blade Tip,” ASME J. Turbomach., 133(2), p. 021028. [CrossRef]
Devore, J. , 2011, Probability and Statistics for Engineering and the Sciences, Cengage Learning, Boston, MA.
Coleman, H. W. , and Steele, W. G. , 2009, Experimentation, Validation, and Uncertainty Analysis for Engineers, Wiley, New York.
Sen, B. , Schmidt, D. L. , and Bogard, D. G. , 1996, “ Film Cooling With Compound Angle Holes: Heat Transfer,” ASME J. Turbomach., 118(4), pp. 800–806. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Transonic wind tunnel facility in the present study

Grahic Jump Location
Fig. 2

Test section and the coolant supply system

Grahic Jump Location
Fig. 3

IR camera calibration curve

Grahic Jump Location
Fig. 4

Time histories of the inlet total pressure (P0,i), total temperature (T0,i), and coolant total pressure (P0,c) and total temperature (T0,c) during a blow-down run

Grahic Jump Location
Fig. 5

Linear relationship between heat flux and wall temperature for a selected point during 2 s period of transient measurement

Grahic Jump Location
Fig. 6

Contours of (a) R2 and (b) relative uncertainty for heat transfer coefficient in linear regression (%U) on the blade tip surface for the cooled case (PS9)

Grahic Jump Location
Fig. 7

Computational domain and mesh employed in the present study

Grahic Jump Location
Fig. 8

Contours of the relative difference in HTC between the results from two meshes for the cooled case (PS5): (a) 3 and 5 × 106 and (b) 5 and 7 × 106

Grahic Jump Location
Fig. 9

Nondimensional radially averaged OTL mass flux distribution on the suction side edge of the squealer tip for the cooled case (PS5)

Grahic Jump Location
Fig. 10

Contours of HTC on the blade tip surfaces obtained from experiments (EXP) and CFD using SA and k–ω SST models: (a) uncooled and (b) cooled

Grahic Jump Location
Fig. 11

Circumferentially averaged HTC value: (a) uncooled and (b) cooled

Grahic Jump Location
Fig. 12

Contours of HTC for cooling holes near pressure side: (a) EXP and (b) CFD

Grahic Jump Location
Fig. 13

Contours of HTC for cooling holes along the camber line: (a) EXP and (b) CFD

Grahic Jump Location
Fig. 14

Contours of HTC for cooling holes near suction side: (a) EXP and (b) CFD

Grahic Jump Location
Fig. 15

Contours of cooling effectiveness for the nine-hole case: (a) EXP and (b) CFD

Grahic Jump Location
Fig. 16

Contours of net heat flux reduction for the case with nine holes: (a) EXP and (b) 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