Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31107
Heat Transfer Characteristics on Blade Tip with Unsteady Wake

Authors: Minho Bang, Seok Min Choi, Jun Su Park, Hokyu Moon, Hyung Hee Cho


Present study investigates the effect of unsteady wakes on heat transfer in blade tip. Heat/mass transfer was measured in blade tip region depending on a variety of strouhal number by naphthalene sublimation technique. Naphthalene sublimation technique measures heat transfer using a heat/mass transfer analogy. Experiments are performed in linear cascade which is composed of five turbine blades and rotating rods. Strouhal number of inlet flow are changed ranging from 0 to 0.22. Reynolds number is 100,000 based on 11.4 m/s of outlet flow and axial chord length. Three different squealer tip geometries such as base squealer tip, vertical rib squealer tip, and camber line squealer tip are used to study how unsteady wakes affect heat transfer on a blade tip. Depending on squealer tip geometry, different flow patterns occur on a blade tip. Also, unsteady wakes cause reduced tip leakage flow and turbulent flow. As a result, as strouhal number increases, heat/mass transfer coefficients decrease due to the reduced leakage flow. As strouhal number increases, heat/ mass transfer coefficients on a blade tip increase in vertical rib squealer tip.

Keywords: Heat Transfer, Gas Turbine, blade tip, unsteady wakes

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1306


[1] R. S. Bunker, “A Review of Turbine Blade Tip Heat Transfer,” Annals of the New York Academy of Sciences, Vol 934, pp.64-79, 2001.
[2] B. Sunden and G. Xie, “Gas Turbine Blade Tip Heat Transfer and Cooling: A Literature Survey,” Heat Transfer Engineering, Vol 31, pp.527-554, 2010.
[3] M. K. Chyu, H. K. Moon, and D. E. Metzger, Heat Transfer in the Tip Region of Grooved Turbine Blades, Journal of Turbomachinery, Vol 2, pp131-138, 1989.
[4] H. H. Cho, D. Rhee, and J. H. Choi, "Heat/Mass Transfer Characteristics on Turbine Shroud with Blade Tip Clearance," Annals of The New York Academy of Sciences, Vol. 934, pp. 281-288, 2001.
[5] D. Rhee and H. H. Cho, "Local Heat/Mass Transfer characteristics on a Rotating Blade with Flat Tip in Low-Speed Annular Cascade-Part I: Near-Tip Surface", ASME J. of Turbomachinery, Vol. 128, No. 1, pp. 96-109, 2006.
[6] D. Rhee and H. H. Cho, "Effect of Vane/Blade Relative Position on Heat Transfer Characteristics in a Stationary Turbine Blade: Part 1- Tip and Shroud," International Journal of Thermal Sciences, Vol. 47, pp. 1528 – 1543, 2008.
[7] J. S. Kwak and J. C. Han, “Heat-Transfer Coefficients of a Turbine Blade-Tip and Near-Tip Regions,”, Vol. 17, pp. 297-303, 2003.
[8] G. S. Azad, J. C. Han and R. J. Boyle, “Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade,” Journal of Turbomachinery, Vol. 122, pp. 725-732, 2000.
[9] V. Saxena, H. Nasir and S. V. Ekkad, “Effect of Blade Tip Geometry on Tip Flow and Heat Transfer for a Blade in a Low-Speed Cascade,” Journal of Turbomachinery, Vol. 126, pp. 130–138, 2004.
[10] V. Saxena and S. V. Ekkad, “Effect of Squealer Geometry on Tip Flow and Heat Transfer for a Turbine Blade in a Low Speed Cascade,” Journal of Heat Transfer, Vol. 126, pp. 546-553, 2004.
[11] S. M. Choi, J. S. Park, H. Chung, B. M. Chang, and H. H. Cho, “Effect of Unsteady Wakes on Local Heat Transfer of 1st Stage Blade Endwall,” Proceedings of ASME Turbo Expo 2015, pp. V05BT13A024, 2015.
[12] R. J. Goldstein and H. H. Cho, “A Review of Mass Transfer Measurements Using Naphthalene Sublimation,” Experimental Thermal and Fluid Science, Vol. 10, pp. 416-434, 1995.