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Comparisons of Heat Transfer Enhancement of an Internal Blade Tip with Metal or Insulating Pins

Published online by Cambridge University Press:  03 June 2015

Gongnan Xie*
Affiliation:
The Key Laboratory of Contemporary Design and Integrated Manufacturing Technology, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China Division of Heat Transfer, Lund University, SE-22100, Lund, Sweden
Bengt Sundén*
Affiliation:
Division of Heat Transfer, Lund University, SE-22100, Lund, Sweden
*
Corresponding author. URL: http://www.ht.energy.lth.se/personal/bengt_sunden Email: [email protected]
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Abstract

Cooling methods are needed for turbine blade tips to ensure a long durability and safe operation. A common way to cool a tip is to use serpentine passages with 180-deg turn under the blade tip-cap taking advantage of the three-dimensional turning effect and impingement like flow. Improved internal convective cooling is therefore required to increase the blade tip lifetime. In the present study, augmented heat transfer of an internal blade tip with pin-fin arrays has been investigated numerically using a conjugate heat transfer method. The computational domain includes the fluid region and the solid pins as well as the tip regions. Turbulent convective heat transfer between the fluid and pins, and heat conduction within pins and tip are simultaneously computed. The main objective of the present study is to observe the effect of the pin material on heat transfer enhancement of the pin-finned tips. It is found that due to the combination of turning, impingement and pin-fin crossflow, the heat transfer coefficient of a pin-finned tip is a factor of 2.9 higher than that of a smooth tip at the cost of an increased pressure drop by less than 10%. The usage of metal pins can reduce the tip temperature effectively and thereby remove the heat load from the tip. Also, it is found that the tip heat transfer is enhanced even by using insulating pins having low thermal conductivity at low Reynolds numbers. The comparisons of overall performances are also included.

Type
Research Article
Copyright
Copyright © Global-Science Press 2011

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References

[1] Hwang, J. J., Lia, T. Y., and Chen, S. H., Prediction of turbulent fluid flow and heat transfer in a rotating periodical two-pass square duct, Int. J. Numer. Methods. Heat. Fluid. Flow., 8 (1998), pp. 519538.CrossRefGoogle Scholar
[2] Chen, H. C., Jang, Y. J., and Han, J. C., Computation of heat transfer in rotating two-pass square channels by a second-moment closure model, Int. J. Heat. Mass. Trans., 43 (2000), pp. 603616.CrossRefGoogle Scholar
[3] Iacovides, H., and Raisee, M., Computation of flow and heat transfer in two-dimensional rib-roughened passages using low-Reynolds-number turbulence models, Int. J. Numer. Methods. Heat. Fluid. Flow., 11 (2001), pp. 138155.CrossRefGoogle Scholar
[4] Nonino, C., and Comini, G., Convective heat transfer in ribbed square channel, Int. J. Numer. Methods. Heat. Fluid. Flow., 12 (2002), pp. 610628.CrossRefGoogle Scholar
[5] Jia, R., Rokni, M., and Sundén, B., Impingement cooling in a rib-roughened channel with cross-flow, Int. J. Numer. Methods. Heat. Fluid. Flow., 11 (2001), pp. 642662.CrossRefGoogle Scholar
[6] Sundén, B., Jia, R., and Abdon, A., Computation of combined turbulent convective and impingement heat transfer, Int. J. Numer. Methods. Heat. Fluid. Flow., 14 (2004), pp. 116133.CrossRefGoogle Scholar
[7] Metzger, D. E., Berry, R. A., and Bronson, J. P., Developing heat transfer in rectangular ducts with staggered arrays of short pin fins, ASME J. Heat. Trans., 104 (1982), pp. 700706.CrossRefGoogle Scholar
[8] Lau, S. C., Kim, Y. S., and Han, J. C., Local endwall heat/ mass distributions in pin fin channels, AIAA J. Thermophys., 1 (1987), pp. 365372.CrossRefGoogle Scholar
[9] Chyu, M. K., Hsing, Y. C., Shih, T. I. P., and Natarajan, V., Heat transfer contributions of pins and endwall in pin-fin arrays: effect of thermal boundary condition modelling, ASME J. Turbomachinery., 121 (1999), pp. 257263.CrossRefGoogle Scholar
[10] Goldstein, R. J., Jabbari, M. Y., and Chen, S. B., Convective mass transfer and pressure loss characteristics of staggered short pin-fin arrays, Int. J. Heat. Mass. Trans., 37 (1994), pp. 149160.CrossRefGoogle Scholar
[11] Wright, L. M., Lee, E., and Han, J. C., Effect of rotating on heat transfer in rectangular channels with pin fins, AIAA J. Thermophys. Heat. Trans., 18 (2004), pp. 263272.CrossRefGoogle Scholar
[12] Ames, F. E., Dvorak, L. A., and Morrow, M. J., Turbulent augmentation of internal convection over pins in staggered-pin fin arrays, ASME J. Turbomachinery., 127 (2005), pp. 183– 190.CrossRefGoogle Scholar
[13] Sahiti, N., Lemouedda, A., Stojkovic, D., Durst, F., and Franz, E., Performance comparison of pin fin in-duct flow arrays with various pin cross-section, Appl. Thermal. Eng., 26 (2006), pp. 1761192.CrossRefGoogle Scholar
[14] Su, G. G., Chen, H. C., and Han, J. C., Computation of flow and heat transfer in rotating rectangular channels (AR = 4: 1) with pin-fins by a Reynolds stress turbulence model, ASME J. Heat. Trans., 129 (2007), pp. 685696.CrossRefGoogle Scholar
[15] Chang, S. W., Yang, T. L., Huang, C. C., and Chiang, K. F., Endwall heat transfer and pressure drop in rectangular channels with attached and detached circular pin-fin array, Int. J. Heat. Mass. Trans., 51 (2008), pp. 52475259.CrossRefGoogle Scholar
[16] Bunker, R. S., The augmentation of internal blade tip-cap cooling by arrays of shaped pins, Proceedings of GT2007, ASME Turbo 2007, paper no. GT2007-27009.CrossRefGoogle Scholar
[17] Xie, G. N., Sundén, B., Wang, L., and Utriainen, E., Enhanced heat transfer on the tipwall in a rectangular two-pass channel by pin-fin arrays, Numer. Heat. Trans., 53 (2009), pp. 739761.CrossRefGoogle Scholar
[18] Xie, G. N., Sundén, B., Utrainen, E., and Wang, L., Computational analysis of pin-fin arrays effects of internal heat transfer enhancement of a blade tip-wall, ASME J. Heat. Trans., 132 (2010), 031901.CrossRefGoogle Scholar
[19] Xie, G. N., Sundén, B., Wang, L., and Utriainen, E., Augmented heat transfer of an internal blade tip by full or partial arrays of pin-fins, Int. Symp. Heat. Trans. Gas. Turb. Sys., 9-14 August 2009, Antalya, Turkey.Google Scholar
[20] Xie, G. N., and Sundén, B., Conjugated heat transfer enhancement of an internal blade pin-finned tip, Proceedings of 2009 ASME International Mechanical Engineering Congress and Exposition, IMECE2009, November 13-19, 2009, Lake Buena Vista, Florida, USA, paper no. IMECE2009-10296.Google Scholar
[21] Xie, G. N., and Sundén, B., Conjugated analysis of heat transfer enhancement of an internal blade tip-wall with pin-fin arrays, J. Enhanced. Heat. Trans., accepted, in press.Google Scholar
[22] Shih, T.-H., Liou, W. W., Shabbir, A., Yang, Z., and Zhu, J., A new k - ε eddy-viscosity model for high Reynolds number turbulent flows model development and validation, Comput. Fluids., 24 (1995), pp. 227238.CrossRefGoogle Scholar