Advanced

On the Improvement of the Poor Heat Transfer Lee-Side Regions of Square Cross-Section Ribbed Channels.

Zheng, Shaofei; Ji, Tingwu; Xie, Gongnan and Sundén, Bengt LU (2014) In Numerical Heat Transfer Part A: Applications 66(9). p.963-989
Abstract
Heat transfer and flow characteristics of six ribbed channels of square cross section having different rib structure are computed with the objective of improving heat transfer in the lee-side of the ribs. Six ribs are installed on the bottom walls of each channel. The rib pitch-to-height ratio (P/e) is 10. Details of the turbulent flow structure, temperature fields, local heat transfer coefficients, flow friction coefficients, normalized heat transfer rates, and normalized friction factors are reported. The simulations use the v(2)f turbulence model and inlet Reynolds number range of 8,000 to 24,000. A uniform heat flux is appropriately applied on all surfaces. The heat transfer performances features of the ribbed channels of various... (More)
Heat transfer and flow characteristics of six ribbed channels of square cross section having different rib structure are computed with the objective of improving heat transfer in the lee-side of the ribs. Six ribs are installed on the bottom walls of each channel. The rib pitch-to-height ratio (P/e) is 10. Details of the turbulent flow structure, temperature fields, local heat transfer coefficients, flow friction coefficients, normalized heat transfer rates, and normalized friction factors are reported. The simulations use the v(2)f turbulence model and inlet Reynolds number range of 8,000 to 24,000. A uniform heat flux is appropriately applied on all surfaces. The heat transfer performances features of the ribbed channels of various designs are evaluated and compared. A case with an inclined lee-side structure having an inclination angle of 160 degrees yields the highest Nusselt number and friction factor, about 4.6%-6.4% higher than those with rectangular ribs, and 7.1%-9.0% higher heat transfer when the heated-surface area is considered. Increased pressure drop is kept within certain limits when considering the balance between cooling effectiveness and pressure loss for the comparisons. Though having the best heat transfer, the case with the inclined back-wall geometry of the ribs does not present the better overall thermal performance due to the higher friction. The heat transfer enhancement is more prominent when improvements of the poor heat transfer regions downstream of the rib are computed with the surface area change excluded. A conclusion to be drawn is that lee-side improvement of heat transfer can be effected with suitable design of the rib downstream side. This finding can be applied to improvement of turbine airfoil cooling. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Numerical Heat Transfer Part A: Applications
volume
66
issue
9
pages
963 - 989
publisher
Taylor & Francis
external identifiers
  • wos:000339327100001
  • scopus:84904464522
ISSN
1040-7782
DOI
10.1080/10407782.2014.894396
language
English
LU publication?
yes
id
640c1508-dd0f-4646-abfc-aa6a0d53e849 (old id 4598852)
date added to LUP
2014-09-05 11:00:00
date last changed
2017-07-30 04:05:36
@article{640c1508-dd0f-4646-abfc-aa6a0d53e849,
  abstract     = {Heat transfer and flow characteristics of six ribbed channels of square cross section having different rib structure are computed with the objective of improving heat transfer in the lee-side of the ribs. Six ribs are installed on the bottom walls of each channel. The rib pitch-to-height ratio (P/e) is 10. Details of the turbulent flow structure, temperature fields, local heat transfer coefficients, flow friction coefficients, normalized heat transfer rates, and normalized friction factors are reported. The simulations use the v(2)f turbulence model and inlet Reynolds number range of 8,000 to 24,000. A uniform heat flux is appropriately applied on all surfaces. The heat transfer performances features of the ribbed channels of various designs are evaluated and compared. A case with an inclined lee-side structure having an inclination angle of 160 degrees yields the highest Nusselt number and friction factor, about 4.6%-6.4% higher than those with rectangular ribs, and 7.1%-9.0% higher heat transfer when the heated-surface area is considered. Increased pressure drop is kept within certain limits when considering the balance between cooling effectiveness and pressure loss for the comparisons. Though having the best heat transfer, the case with the inclined back-wall geometry of the ribs does not present the better overall thermal performance due to the higher friction. The heat transfer enhancement is more prominent when improvements of the poor heat transfer regions downstream of the rib are computed with the surface area change excluded. A conclusion to be drawn is that lee-side improvement of heat transfer can be effected with suitable design of the rib downstream side. This finding can be applied to improvement of turbine airfoil cooling.},
  author       = {Zheng, Shaofei and Ji, Tingwu and Xie, Gongnan and Sundén, Bengt},
  issn         = {1040-7782},
  language     = {eng},
  number       = {9},
  pages        = {963--989},
  publisher    = {Taylor & Francis},
  series       = {Numerical Heat Transfer Part A: Applications},
  title        = {On the Improvement of the Poor Heat Transfer Lee-Side Regions of Square Cross-Section Ribbed Channels.},
  url          = {http://dx.doi.org/10.1080/10407782.2014.894396},
  volume       = {66},
  year         = {2014},
}