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Non-axisymmetric Endwall film cooling characteristics considering the influences of cylindrical holes and laidback fan-shaped holes

Du, Kun ; Jia, Yihao ; Liu, Cunliang and Sunden, Bengt LU (2024) In International Journal of Heat and Mass Transfer 225.
Abstract

Flow fields near the turbine vane endwall are complicated due to the endwall cross flows. The use of a non-axisymmetric endwall is regarded as an efficient technique to reduce the lateral pressure difference, decreasing the endwall cross flow. Numerical analysis was performed to determine how the non-axisymmetric endwall affected the vortex structure and heat transfer level. The cooling performance was investigated with cylindrical and laidback fan-shaped holes (7–7–7), which were arranged in rows aligned in the axial direction. The results showed that the non-axisymmetric endwall could significantly reduce the circumferential pressure difference and suppress the growth of the passage vortex, and the area-averaged heat transfer... (More)

Flow fields near the turbine vane endwall are complicated due to the endwall cross flows. The use of a non-axisymmetric endwall is regarded as an efficient technique to reduce the lateral pressure difference, decreasing the endwall cross flow. Numerical analysis was performed to determine how the non-axisymmetric endwall affected the vortex structure and heat transfer level. The cooling performance was investigated with cylindrical and laidback fan-shaped holes (7–7–7), which were arranged in rows aligned in the axial direction. The results showed that the non-axisymmetric endwall could significantly reduce the circumferential pressure difference and suppress the growth of the passage vortex, and the area-averaged heat transfer coefficient was reduced by 3.34%. The outlet area of the film hole was altered by the non-axisymmetric endwall, and the over-cooled regions may have appeared as a result of the excessive area increase. The influence of the non-axisymmetric endwall was concentrated at 0.4 < Z/Cax < 1.0 for the cylindrical hole. With the increase in M, the film cooling effectiveness of the non-axisymmetric endwall attained a higher level than that of the flat endwall. For the laidback fan-shaped hole, the effect of the non-axisymmetric endwall was confined within 0.25 < Z/Cax < 1.0. The half-period trigonometric function of the non-axisymmetric endwall (HTFN) achieved the optimal cooling performance for three blowing ratios. However, the periodic trigonometric function of the non-axisymmetric endwall (PTFN) only outperformed the flat endwall when M= 1.5.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aerodynamic characteristics, Film cooling, Laidback Fan-shaped Hole, Non-axisymmetric endwall
in
International Journal of Heat and Mass Transfer
volume
225
article number
125403
publisher
Pergamon Press Ltd.
external identifiers
  • scopus:85188026662
ISSN
0017-9310
DOI
10.1016/j.ijheatmasstransfer.2024.125403
language
English
LU publication?
yes
id
7cd16412-cd78-49fd-8772-9740a059ddbf
date added to LUP
2024-04-04 13:14:04
date last changed
2024-04-04 13:15:13
@article{7cd16412-cd78-49fd-8772-9740a059ddbf,
  abstract     = {{<p>Flow fields near the turbine vane endwall are complicated due to the endwall cross flows. The use of a non-axisymmetric endwall is regarded as an efficient technique to reduce the lateral pressure difference, decreasing the endwall cross flow. Numerical analysis was performed to determine how the non-axisymmetric endwall affected the vortex structure and heat transfer level. The cooling performance was investigated with cylindrical and laidback fan-shaped holes (7–7–7), which were arranged in rows aligned in the axial direction. The results showed that the non-axisymmetric endwall could significantly reduce the circumferential pressure difference and suppress the growth of the passage vortex, and the area-averaged heat transfer coefficient was reduced by 3.34%. The outlet area of the film hole was altered by the non-axisymmetric endwall, and the over-cooled regions may have appeared as a result of the excessive area increase. The influence of the non-axisymmetric endwall was concentrated at 0.4 &lt; Z/C<sub>ax</sub> &lt; 1.0 for the cylindrical hole. With the increase in M, the film cooling effectiveness of the non-axisymmetric endwall attained a higher level than that of the flat endwall. For the laidback fan-shaped hole, the effect of the non-axisymmetric endwall was confined within 0.25 &lt; Z/C<sub>ax</sub> &lt; 1.0. The half-period trigonometric function of the non-axisymmetric endwall (HTFN) achieved the optimal cooling performance for three blowing ratios. However, the periodic trigonometric function of the non-axisymmetric endwall (PTFN) only outperformed the flat endwall when M= 1.5.</p>}},
  author       = {{Du, Kun and Jia, Yihao and Liu, Cunliang and Sunden, Bengt}},
  issn         = {{0017-9310}},
  keywords     = {{Aerodynamic characteristics; Film cooling; Laidback Fan-shaped Hole; Non-axisymmetric endwall}},
  language     = {{eng}},
  month        = {{06}},
  publisher    = {{Pergamon Press Ltd.}},
  series       = {{International Journal of Heat and Mass Transfer}},
  title        = {{Non-axisymmetric Endwall film cooling characteristics considering the influences of cylindrical holes and laidback fan-shaped holes}},
  url          = {{http://dx.doi.org/10.1016/j.ijheatmasstransfer.2024.125403}},
  doi          = {{10.1016/j.ijheatmasstransfer.2024.125403}},
  volume       = {{225}},
  year         = {{2024}},
}