Advanced

Predictions of Enhanced Heat Transfer of an Internal Blade Tip-Wall with Hemishperical Dimples or Protrusions

Xie, Gongnan LU ; Sundén, Bengt LU and Wang, Qiuwang (2010) ASME Turbo Expo 2010 In Proceedings of the Asme Turbo Expo 2010, Volume 4: Heat Transfer, Parts A and B p.91-100
Abstract
The blade tip region encounters high thermal loads because of the hot gas leakage flows, and it must therefore be cooled to ensure a long durability and safe operation. A common way to cool a blade tip is to design serpentine passages with 180-deg turn under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase the blade tip lifetime. Dimples and protrusions are well recognized as effective devices to augment heat transfer in various applications. In this paper, enhanced heat transfer of an internal blade tip-wall has been predicted numerically. The computational models consist of a two-pass channel with 180-deg turn and arrays of hemispherical dimples or protrusions internally... (More)
The blade tip region encounters high thermal loads because of the hot gas leakage flows, and it must therefore be cooled to ensure a long durability and safe operation. A common way to cool a blade tip is to design serpentine passages with 180-deg turn under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase the blade tip lifetime. Dimples and protrusions are well recognized as effective devices to augment heat transfer in various applications. In this paper, enhanced heat transfer of an internal blade tip-wall has been predicted numerically. The computational models consist of a two-pass channel with 180-deg turn and arrays of hemispherical dimples or protrusions internally mounted on the tip-wall. Inlet Reynolds numbers are in the range of 100,000 to 600,000. The computations are three dimensional, steady, incompressible and non-rotating. The overall performance of the two-pass channels is also evaluated. It is found that due to the combination of turning impingement and protrusion crossflow or dimple advection, the heat transfer coefficient of the augmented tip is a factor of 2.0 higher than that of a smooth tip. This augmentation is achieved at the cost of a penalty of pressure drop by around 5%. By comparing the present dimples or protrusions performance with others in previous works, it is found that the augmented-tips show the best performance, and the dimpled or protruded tips are superior to those pin-finned tips when the active area enhancement is excluded. It is suggested that dimples and protrusions can be used to enhance blade tip heat transfer and hence improve blade tip cooling. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Enhanced heat transfer, Blade tip-wall, Dimples, Protrusions, Prediction
in
Proceedings of the Asme Turbo Expo 2010, Volume 4: Heat Transfer, Parts A and B
pages
91 - 100
publisher
American Society Of Mechanical Engineers (ASME)
conference name
ASME Turbo Expo 2010
external identifiers
  • WOS:000290693500009
  • Scopus:82055191641
ISBN
978-0-7918-4399-4
DOI
10.1115/GT2010-22265
language
English
LU publication?
yes
id
b139eb77-dabd-4d21-9180-9429619d05d7 (old id 1984573)
date added to LUP
2011-07-11 09:38:12
date last changed
2016-10-13 04:50:18
@misc{b139eb77-dabd-4d21-9180-9429619d05d7,
  abstract     = {The blade tip region encounters high thermal loads because of the hot gas leakage flows, and it must therefore be cooled to ensure a long durability and safe operation. A common way to cool a blade tip is to design serpentine passages with 180-deg turn under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase the blade tip lifetime. Dimples and protrusions are well recognized as effective devices to augment heat transfer in various applications. In this paper, enhanced heat transfer of an internal blade tip-wall has been predicted numerically. The computational models consist of a two-pass channel with 180-deg turn and arrays of hemispherical dimples or protrusions internally mounted on the tip-wall. Inlet Reynolds numbers are in the range of 100,000 to 600,000. The computations are three dimensional, steady, incompressible and non-rotating. The overall performance of the two-pass channels is also evaluated. It is found that due to the combination of turning impingement and protrusion crossflow or dimple advection, the heat transfer coefficient of the augmented tip is a factor of 2.0 higher than that of a smooth tip. This augmentation is achieved at the cost of a penalty of pressure drop by around 5%. By comparing the present dimples or protrusions performance with others in previous works, it is found that the augmented-tips show the best performance, and the dimpled or protruded tips are superior to those pin-finned tips when the active area enhancement is excluded. It is suggested that dimples and protrusions can be used to enhance blade tip heat transfer and hence improve blade tip cooling.},
  author       = {Xie, Gongnan and Sundén, Bengt and Wang, Qiuwang},
  isbn         = {978-0-7918-4399-4},
  keyword      = {Enhanced heat transfer,Blade tip-wall,Dimples,Protrusions,Prediction},
  language     = {eng},
  pages        = {91--100},
  publisher    = {ARRAY(0xc305410)},
  series       = {Proceedings of the Asme Turbo Expo 2010, Volume 4: Heat Transfer, Parts A and B},
  title        = {Predictions of Enhanced Heat Transfer of an Internal Blade Tip-Wall with Hemishperical Dimples or Protrusions},
  url          = {http://dx.doi.org/10.1115/GT2010-22265},
  year         = {2010},
}