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Enhanced heat transfer in a labyrinth channels with ribs of different shape

Wei Du (Lund University, Lund, Sweden)
Lei Luo (School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China)
Songtao Wang (Harbin Institute of Technology, Harbin, China)
Jian Liu (Department of Energy Sciences, Lund University, Lund, Sweden)
Bengt Ake Sunden (Department of Energy Sciences, Lund University, Lund, Sweden)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 29 August 2019

Issue publication date: 16 January 2020

Abstract

Purpose

The purpose of this study is to enhance the thermal performance in the labyrinth channel by different ribs shape. The labyrinth channel is a relatively new cooling structure to decrease the temperature near the trailing region of gas turbine.

Design/methodology/approach

Based on the geometric similarity, a simplified geometric model is used. The k − ω turbulence model is used to close the Navier–Stokes equations. Five rib shapes (one rectangular rib, two arched ribs and two trapezoid ribs) and five Reynolds numbers (10,000 to 50,000) are considered. The Nusselt number, flow structure and friction factor are analyzed.

Findings

Nusselt number is tightly related to the rib shape in the labyrinth channel. The different shapes of the ribs result in different horseshoe vortex and wake region. In general, the arched rib brings the highest Nusselt number and friction factor. The Nusselt number is increased by 15.8 per cent compared to that of trapezoidal ribs. High Nusselt number is accompanied by the high friction factor in a labyrinth channels. The friction factor is increased by 64.6 per cent compared to rectangular ribs. However, the rib shape has a minor effect on the overall thermal performance.

Practical implications

This study is useful to protect the trailing region of advanced gas turbine.

Originality/value

This paper presents the flow structure and heat transfer characteristics in a labyrinth channel with different rib shapes.

Keywords

Acknowledgements

The authors acknowledge the financial support provided by China Scholarship Council (CSC), Natural Science Foundation of China (No. 51706051), China postdoctoral science foundation funded project (No. 2017M620116), Heilongjiang Postdoctoral Fund (No. LBH-Z17066), the General and Special Program of the Postdoctoral Science Foundation of China (No. 2018T110296) and the Fundamental Research Funds for the Central Universities (Grant No. HIT.NSRIF.2019061).

Citation

Du, W., Luo, L., Wang, S., Liu, J. and Sunden, B.A. (2020), "Enhanced heat transfer in a labyrinth channels with ribs of different shape", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 30 No. 2, pp. 724-741. https://doi.org/10.1108/HFF-05-2019-0393

Publisher

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Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited