Advanced

Heat transfer and friction factor in a dimple-pin fin wedge duct with various dimple depth and converging angle

Lei, Luo LU ; Wang, Chenglong LU ; Wang, Lei LU ; Sunden, Bengt Ake LU and Wang, Songtao (2016) In International Journal of Numerical Methods for Heat and Fluid Flow 26(6). p.1954-1974
Abstract

Purpose - The dimple is adopted into a pin fin wedge duct which is widely used in modern gas turbine vane cooling structure trailing edge region. The purpose of this paper is to study the effects of dimple depth and duct converging angle on the endwall heat transfer and friction factor in this pin fin wedge duct. Design/methodology/approach - The study is carried out by using the numerical simulations. The diameter of dimples is the same as the pin fin diameter with an inline manner arrangement in relation to the pin fin. The ratio between dimple depth and dimple diameter is varied from 0 to 0.3 and the converging angle is ranging from 0° to 12.7°. The Reynolds number is between 10,000 and 50,000. Results of the endwall Nusselt number,... (More)

Purpose - The dimple is adopted into a pin fin wedge duct which is widely used in modern gas turbine vane cooling structure trailing edge region. The purpose of this paper is to study the effects of dimple depth and duct converging angle on the endwall heat transfer and friction factor in this pin fin wedge duct. Design/methodology/approach - The study is carried out by using the numerical simulations. The diameter of dimples is the same as the pin fin diameter with an inline manner arrangement in relation to the pin fin. The ratio between dimple depth and dimple diameter is varied from 0 to 0.3 and the converging angle is ranging from 0° to 12.7°. The Reynolds number is between 10,000 and 50,000. Results of the endwall Nusselt number, friction factor, and flow structures are included. For convenience of comparison, the pin fin wedge duct with a converging angle of 12.7° without dimples is considered as the baseline. Findings - It is found that the dimples can effectively enhance the endwall heat transfer due to the impingement on the dimple surface, reattachment downstream the dimple and recirculation in front of the pin fin leading edge. By increasing the converging angle, the heat transfer is also increased but with a large friction factor penalty. In addition, the heat transfer enhancement for deep depth cases is 1.57 times higher than that of the low depth case. The thermal performance indicates that the intensity of heat transfer enhancement depends upon the dimple depth and converging angle. Originality/value - It suggests that the endwall heat transfer in a pin fin wedge duct can be increase by the adoption of dimples. The optimal dimple relative depth is 0.2 with low friction factor and high heat transfer performance.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Converging angle, Dimple depth, Friction factor, Heat transfer, Numerical simulation, Pin fin wedge duct
in
International Journal of Numerical Methods for Heat and Fluid Flow
volume
26
issue
6
pages
21 pages
publisher
Emerald Group Publishing Limited
external identifiers
  • scopus:84982792134
  • wos:000382547100017
ISSN
0961-5539
DOI
10.1108/HFF-02-2015-0043
language
English
LU publication?
yes
id
4ad5811a-59c0-4848-b4b2-9ab74af621ad
date added to LUP
2016-12-14 11:55:18
date last changed
2017-09-18 11:31:19
@article{4ad5811a-59c0-4848-b4b2-9ab74af621ad,
  abstract     = {<p>Purpose - The dimple is adopted into a pin fin wedge duct which is widely used in modern gas turbine vane cooling structure trailing edge region. The purpose of this paper is to study the effects of dimple depth and duct converging angle on the endwall heat transfer and friction factor in this pin fin wedge duct. Design/methodology/approach - The study is carried out by using the numerical simulations. The diameter of dimples is the same as the pin fin diameter with an inline manner arrangement in relation to the pin fin. The ratio between dimple depth and dimple diameter is varied from 0 to 0.3 and the converging angle is ranging from 0° to 12.7°. The Reynolds number is between 10,000 and 50,000. Results of the endwall Nusselt number, friction factor, and flow structures are included. For convenience of comparison, the pin fin wedge duct with a converging angle of 12.7° without dimples is considered as the baseline. Findings - It is found that the dimples can effectively enhance the endwall heat transfer due to the impingement on the dimple surface, reattachment downstream the dimple and recirculation in front of the pin fin leading edge. By increasing the converging angle, the heat transfer is also increased but with a large friction factor penalty. In addition, the heat transfer enhancement for deep depth cases is 1.57 times higher than that of the low depth case. The thermal performance indicates that the intensity of heat transfer enhancement depends upon the dimple depth and converging angle. Originality/value - It suggests that the endwall heat transfer in a pin fin wedge duct can be increase by the adoption of dimples. The optimal dimple relative depth is 0.2 with low friction factor and high heat transfer performance.</p>},
  author       = {Lei, Luo and Wang, Chenglong and Wang, Lei and Sunden, Bengt Ake and Wang, Songtao},
  issn         = {0961-5539},
  keyword      = {Converging angle,Dimple depth,Friction factor,Heat transfer,Numerical simulation,Pin fin wedge duct},
  language     = {eng},
  month        = {08},
  number       = {6},
  pages        = {1954--1974},
  publisher    = {Emerald Group Publishing Limited},
  series       = {International Journal of Numerical Methods for Heat and Fluid Flow},
  title        = {Heat transfer and friction factor in a dimple-pin fin wedge duct with various dimple depth and converging angle},
  url          = {http://dx.doi.org/10.1108/HFF-02-2015-0043},
  volume       = {26},
  year         = {2016},
}