Effect of wall curvature on heat transfer and hydrodynamics in a ribbed cooling passage
(2024) In International Journal of Heat and Fluid Flow 106.- Abstract
Simplified rectangular ribbed cooling passages with a flat wall are extensively considered in exploring the internal cooling features of turbine blades, but the realistic blade has a twisted shape inherently. The effects induced by the curved wall have not been clarified in detail. In this work, adopting a verified v2f turbulence model, numerical investigations are completed to evaluate the effects of the curved wall on the internal cooling characteristics of a ribbed channel. Adopting the unified ribbed channel, flat, convex, and concave walls with distinct curvatures are comprehensively evaluated and compared in a wide Re range for the turbulent flow and heat transfer features as well as the flow and thermal performance. It... (More)
Simplified rectangular ribbed cooling passages with a flat wall are extensively considered in exploring the internal cooling features of turbine blades, but the realistic blade has a twisted shape inherently. The effects induced by the curved wall have not been clarified in detail. In this work, adopting a verified v2f turbulence model, numerical investigations are completed to evaluate the effects of the curved wall on the internal cooling characteristics of a ribbed channel. Adopting the unified ribbed channel, flat, convex, and concave walls with distinct curvatures are comprehensively evaluated and compared in a wide Re range for the turbulent flow and heat transfer features as well as the flow and thermal performance. It is found that using the flat wall, ribs can typically induce recirculation vortices having a two-dimensional nature. In contrast, the curved wall significantly contributes to the counter-rotating vortex pairs on the spanwise plane. Combined with recirculation vortices offered by the ribs, the turbulent flow of the cooling channel with the curved wall has a remarkable three-dimensional feature. Hence, the turbulent activity and fluid mixing are enhanced greatly along with the raised heat transfer enhancement and friction loss. Particularly, the convex wall with a curvature of K = 4 provides 28.6 % higher heat transfer performance (Nu/Nu0) but 88.4 % higher resistance (f/f0) than the flat wall. Considering the overall cooling performance, the concave wall with a relatively small curvature is suggested with an improvement of up to 32.8 % concerning the factor (Nu/Nu0)/(f/f0) and 9.5 % on (Nu/Nu0)/(f/f0)1/3. Finally, it is highlighted that considering the effect of the wall curvature, the current study stimulates the mechanistic understanding and provides a design guideline for high-performance blade internal cooling.
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- author
- Zheng, Shao Fei ; Lian, Wen Kai ; Meng, Jia Xing ; Yang, Yan Ru ; Gao, Shu Rong ; Sunden, Bengt LU and Wang, Xiao Dong
- organization
- publishing date
- 2024-04
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Cooling performance, Curved wall, Internal cooling, Turbine blade, Turbulent flow and heat transfer
- in
- International Journal of Heat and Fluid Flow
- volume
- 106
- article number
- 109317
- publisher
- Elsevier
- external identifiers
-
- scopus:85185294400
- ISSN
- 0142-727X
- DOI
- 10.1016/j.ijheatfluidflow.2024.109317
- language
- English
- LU publication?
- yes
- id
- 0f3cb494-c023-44a8-abbe-001219125591
- date added to LUP
- 2024-03-14 12:12:35
- date last changed
- 2024-03-14 12:13:45
@article{0f3cb494-c023-44a8-abbe-001219125591,
abstract = {{<p>Simplified rectangular ribbed cooling passages with a flat wall are extensively considered in exploring the internal cooling features of turbine blades, but the realistic blade has a twisted shape inherently. The effects induced by the curved wall have not been clarified in detail. In this work, adopting a verified v<sup>2</sup>f turbulence model, numerical investigations are completed to evaluate the effects of the curved wall on the internal cooling characteristics of a ribbed channel. Adopting the unified ribbed channel, flat, convex, and concave walls with distinct curvatures are comprehensively evaluated and compared in a wide Re range for the turbulent flow and heat transfer features as well as the flow and thermal performance. It is found that using the flat wall, ribs can typically induce recirculation vortices having a two-dimensional nature. In contrast, the curved wall significantly contributes to the counter-rotating vortex pairs on the spanwise plane. Combined with recirculation vortices offered by the ribs, the turbulent flow of the cooling channel with the curved wall has a remarkable three-dimensional feature. Hence, the turbulent activity and fluid mixing are enhanced greatly along with the raised heat transfer enhancement and friction loss. Particularly, the convex wall with a curvature of K = 4 provides 28.6 % higher heat transfer performance (Nu/Nu<sub>0</sub>) but 88.4 % higher resistance (f/f<sub>0</sub>) than the flat wall. Considering the overall cooling performance, the concave wall with a relatively small curvature is suggested with an improvement of up to 32.8 % concerning the factor (Nu/Nu<sub>0</sub>)/(f/f<sub>0</sub>) and 9.5 % on (Nu/Nu<sub>0</sub>)/(f/f<sub>0</sub>)<sup>1/3</sup>. Finally, it is highlighted that considering the effect of the wall curvature, the current study stimulates the mechanistic understanding and provides a design guideline for high-performance blade internal cooling.</p>}},
author = {{Zheng, Shao Fei and Lian, Wen Kai and Meng, Jia Xing and Yang, Yan Ru and Gao, Shu Rong and Sunden, Bengt and Wang, Xiao Dong}},
issn = {{0142-727X}},
keywords = {{Cooling performance; Curved wall; Internal cooling; Turbine blade; Turbulent flow and heat transfer}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{International Journal of Heat and Fluid Flow}},
title = {{Effect of wall curvature on heat transfer and hydrodynamics in a ribbed cooling passage}},
url = {{http://dx.doi.org/10.1016/j.ijheatfluidflow.2024.109317}},
doi = {{10.1016/j.ijheatfluidflow.2024.109317}},
volume = {{106}},
year = {{2024}},
}