liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Investigation of heat transfer and pressure drop of an impinging jet in a cross-flow for cooling of a heated cube
Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology. Division of Energy and Mechanical Engineering, Department of Technology and Build Environment University of Gävle, Gävle, Sweden.
Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology. Division of Energy and Mechanical Engineering, Department of Technology and Build Environment University of Gävle, Gävle, Sweden.
2008 (English)In: Journal of heat transfer, ISSN 0022-1481, E-ISSN 1528-8943, Vol. 130, no 12, 121401-121413 p.Article in journal (Refereed) Published
Abstract [en]

The objective of this study is to investigate the thermal performance and the cost measured in pressure drops of a targeted cooling system with use of an impinging jet in combination with a low-velocity channel flow on a heated wall-mounted cube. The effects of the Reynolds numbers of the impinging jet and the cross-flow, as well as the distance between the top and bottom plates, are investigated. A steady-state 3D computational fluid dynamics model was developed with use of a Reynolds stress model as turbulence model. The geometrical case is a channel with a heated cube in the middle of the base plate and two inlets, one horizontal channel flow and one vertical impinging jet. The numerical model was validated against experimental data with a similar geometrical setup. The velocity field was measured by particle image velocimetry and the surface temperature was measured by an infrared imaging system. This case results in a very complex flow structure where several flow-related phenomena influence the heat transfer rate and the pressure drops. The average heat transfer coefficients on each side of the cube and the pressure loss coefficients are presented; correlations for the average heat transfer coefficient on the cube and the pressure loss coefficients are created.

Place, publisher, year, edition, pages
ASME International , 2008. Vol. 130, no 12, 121401-121413 p.
Keyword [en]
electronics cooling, impinging jet, CFD, RSM
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-16851DOI: 10.1115/1.2969266ISI: 000262842200004OAI: oai:DiVA.org:liu-16851DiVA: diva2:174395
Available from: 2009-02-21 Created: 2009-02-20 Last updated: 2017-12-13Bibliographically approved
In thesis
1. Numerical investigation of the turbulent flow and heat transfer around a heated cube cooled by and impinging jet in a cross-flow
Open this publication in new window or tab >>Numerical investigation of the turbulent flow and heat transfer around a heated cube cooled by and impinging jet in a cross-flow
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Impinging jets are used for many industrial applications where high heat and mass transfer rates are required. The electronic industry is one of the fastest growing industries and applications of cooling technology in this field are of considerable importance. Forced channel flow is frequently used as a cooling technique. In combating the whole thermal load with forced channel flow, excessive flow rates will be required. The typical electronic system contains one or a few high heat–dissipating components. One possible method to face this problem is to divide the channel flow into an impinging jet and a low-velocity cross-flow. The impinging jet is placed over the high heat-dissipating component and provides a local region with high cooling performance, especially at the stagnation point. The cross-flow is important to insure that well-distributed cooling performance is provided at the remaining part of the electronic system, which requires less cooling.

Impinging jets are also of great scientific interest. Extensive experimental and numerical research has been carried out to predict the flow and heat transfer characteristics in the stagnation region of an impinging jet where most of the investigations have been focused on axi–symmetric round impinging jets without any cross-flow.

The purpose of this study is to examine a spot cooling technique consisting of en impinging jet in combination with a low-velocity cross-flow by use of CFD. The cases are limited to a heated wall-mounted cube with different height which is placed in a channel with different heights and cooled by an impinging jet and a cross-flow with different velocities. The study can be divided into three parts: a verification study, a detailed study and a parametric study.

The verification part consists of a verification of two steady-state Reynolds-Averaged Navier-Stokes turbulence models, a v2-f model and a Reynolds Stress Model (RSM). The results show that both models predicted similar results in the near-wall region except in the stagnation region from the impinging jet where the wall-normal turbulent Reynolds stresses and the turbulent kinetic energy where significantly higher in the RSM than in the v2-f model and in the measurements. The general trend was that the predicted surface temperature and the mean velocity field in the free shear-flow, i.e. far from the walls, from the RSM was in better agreement with the measurements than the results from the v2-f model.

The detailed study presents an unsteady simulation by use of Large Eddy Simulation (LES) for a case identical to the verification study in order to predict the time-averaged velocity field, the turbulence characteristics and the heat transfer rate. The agreements between the results from the LES and the measurements were in general improved compared with the RSM and the v2-f model especially in the stagnation region from the impinging jet.

The parametric study is carried out by use of the validated RSM where influence of the velocities of the impinging jet and the cross-flow, the distance between the top and bottom plates, and the height of the cube on the heat transfer rate and on the pressure drops was investigated.

Place, publisher, year, edition, pages
Linköping: LiU-tryck, 2009. 84 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1227
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-52265 (URN)978-91-7393-740-5 (ISBN)
Public defence
2008-12-12, C3, Hus C, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2009-12-14 Created: 2009-12-14 Last updated: 2012-11-14Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Moshfegh, Bahram

Search in DiVA

By author/editor
Moshfegh, Bahram
By organisation
Department of Mechanical EngineeringThe Institute of Technology
In the same journal
Journal of heat transfer
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 95 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf