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Numerical predictions of flow and heat transfer of film cooling with an internal channel roughened by crescent ribs

Liu, Xueting ; Zhang, Guohua LU ; Sunden, Bengt LU and Xie, Gongnan LU (2018) In Numerical Heat Transfer; Part A: Applications 74(9). p.1539-1564
Abstract

This study explores the effects of crescent ribs mounted in an internal cooling channel on the external adiabatic film cooling performance to evaluate the advantage of crescent ribs in gas turbine blade cooling. Three ribs including a transverse rib, a crescent rib concave to the stream-wise direction, and a crescent rib convex to the stream-wise direction are considered. For a fixed mainstream flow Reynolds number, two cross-flow Reynolds numbers and two blowing ratios are taken into account. The results show that the case with a crescent rib concave to the stream-wise direction provides higher film cooling effectiveness both at the lower cross-flow Reynolds number and at the higher cross-flow Reynolds number with higher blowing ratio... (More)

This study explores the effects of crescent ribs mounted in an internal cooling channel on the external adiabatic film cooling performance to evaluate the advantage of crescent ribs in gas turbine blade cooling. Three ribs including a transverse rib, a crescent rib concave to the stream-wise direction, and a crescent rib convex to the stream-wise direction are considered. For a fixed mainstream flow Reynolds number, two cross-flow Reynolds numbers and two blowing ratios are taken into account. The results show that the case with a crescent rib concave to the stream-wise direction provides higher film cooling effectiveness both at the lower cross-flow Reynolds number and at the higher cross-flow Reynolds number with higher blowing ratio while the case with a crescent rib convex to the stream-wise direction performs worst at any condition. It is found that the longitudinal vortices produced by crescent ribs concave to the stream-wise direction can promote the cooling air entering the film hole while that induced by the other crescent ribs are nonbeneficial for the cooling air entering the hole. The results indicated that a lower spiral intensity leads to counter-rotating vortices with lower intensity and thus results in better cooling effectiveness. However, it makes a narrow coverage of the target surface by the coolant, which leads to disadvantages upon the cooling performance. The relative merits among the cases at different cross-flow Reynolds numbers and blowing ratios are investigated based on the dominating mechanism.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Numerical Heat Transfer; Part A: Applications
volume
74
issue
9
pages
26 pages
publisher
Taylor & Francis
external identifiers
  • scopus:85060762910
ISSN
1040-7782
DOI
10.1080/10407782.2018.1538291
language
English
LU publication?
yes
id
bf39753b-8a76-4005-97fa-da1862f44fec
date added to LUP
2019-02-15 11:24:34
date last changed
2022-04-25 21:37:04
@article{bf39753b-8a76-4005-97fa-da1862f44fec,
  abstract     = {{<p>This study explores the effects of crescent ribs mounted in an internal cooling channel on the external adiabatic film cooling performance to evaluate the advantage of crescent ribs in gas turbine blade cooling. Three ribs including a transverse rib, a crescent rib concave to the stream-wise direction, and a crescent rib convex to the stream-wise direction are considered. For a fixed mainstream flow Reynolds number, two cross-flow Reynolds numbers and two blowing ratios are taken into account. The results show that the case with a crescent rib concave to the stream-wise direction provides higher film cooling effectiveness both at the lower cross-flow Reynolds number and at the higher cross-flow Reynolds number with higher blowing ratio while the case with a crescent rib convex to the stream-wise direction performs worst at any condition. It is found that the longitudinal vortices produced by crescent ribs concave to the stream-wise direction can promote the cooling air entering the film hole while that induced by the other crescent ribs are nonbeneficial for the cooling air entering the hole. The results indicated that a lower spiral intensity leads to counter-rotating vortices with lower intensity and thus results in better cooling effectiveness. However, it makes a narrow coverage of the target surface by the coolant, which leads to disadvantages upon the cooling performance. The relative merits among the cases at different cross-flow Reynolds numbers and blowing ratios are investigated based on the dominating mechanism.</p>}},
  author       = {{Liu, Xueting and Zhang, Guohua and Sunden, Bengt and Xie, Gongnan}},
  issn         = {{1040-7782}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{9}},
  pages        = {{1539--1564}},
  publisher    = {{Taylor & Francis}},
  series       = {{Numerical Heat Transfer; Part A: Applications}},
  title        = {{Numerical predictions of flow and heat transfer of film cooling with an internal channel roughened by crescent ribs}},
  url          = {{http://dx.doi.org/10.1080/10407782.2018.1538291}},
  doi          = {{10.1080/10407782.2018.1538291}},
  volume       = {{74}},
  year         = {{2018}},
}