0
Research Papers

Heat Transfer in an Oblique Jet Impingement Configuration With Varying Jet Geometries

[+] Author and Article Information
Simon Schueren

e-mail: simon.schueren@itlr.uni-stuttgart.de

Jens von Wolfersdorf

Institute of Aerospace Thermodynamics (ITLR),
University of Stuttgart,
Pfaffenwaldring 31,
D-70569 Stuttgart, Germany

Shailendra Naik

Alstom Power,
Brown Boveri Strasse 7,
CH-5401 Baden, Switzerland

On wall D, ‘downstream’ corresponds to falling sD' according to the definition of s (see Fig. 4).

1Address all correspondence to this author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received September 21, 2011; final manuscript received October 28, 2011; published online November 1, 2012. Editor: David Wisler.

J. Turbomach 135(2), 021010 (Nov 01, 2012) (10 pages) Paper No: TURBO-11-1214; doi: 10.1115/1.4006598 History: Received September 21, 2011; Revised October 28, 2011

The experimental and numerical heat transfer results in a trapezoidal duct with two staggered rows of inclined impingement jets are presented. The influence of changes in the jet bore geometry on the wall heat transfer is examined. The goal of this project is to minimize the thermal load in an internal gas turbine blade channel and to provide sufficient cooling for local hot spots. The dimensionless pitch is varied between p/djet=3 − 6. For p/djet=3, cylindrical and conically narrowing bores with a cross section reduction of 25% and 50%, respectively, are investigated. The studies are conducted at 10,000Re75,000. Experimental results are obtained using a transient thermochromic liquid crystal technique. The numerical simulations are performed solving the RANS equations with FLUENT using the low- Re k- ω -SST turbulence model. The results show that for a greater pitch, the decreasing interaction between the jets leads to diminished local wall heat transfer. The area averaged Nusselt numbers decrease by up to 15% for p/djet=4.5, and up to 30% for p/djet=6, respectively, if compared to the baseline pitch of p/djet=3. The conical bore design accelerates the jets, thus increasing the area-averaged heat transfer for identical mass-flow by up to 15% and 30% for the moderately and strongly narrowing jets, respectively. A dependency of the displacement between the Nu maximum and the geometric stagnation point from the jet shear layer is shown.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Schematic of an impingement cooled mid-chord passage of a turbine blade

Grahic Jump Location
Fig. 2

Schematic of the experimental facility

Grahic Jump Location
Fig. 3

Schematic of the test section geometry in its baseline configuration

Grahic Jump Location
Fig. 4

Schematic of the test channel

Grahic Jump Location
Fig. 5

Sketch of the cylindrical (left) and conical (right) bore configurations; see Table 1 for details

Grahic Jump Location
Fig. 6

Computational grid

Grahic Jump Location
Fig. 7

Streaklines for p/djet=3, Re=75,000; left: front view; right: back view

Grahic Jump Location
Fig. 8

Vorticity magnitude at Re=75,000 in slides through jet axes and between jets; top: p/djet=3; center: p/djet=4.5; bottom: p/djet=6

Grahic Jump Location
Fig. 9

Experimental results: local Nusselt number ratios at Re=45,000; top: p/djet=3; bottom: p/djet=4.5

Grahic Jump Location
Fig. 10

Numerical results: local Nusselt number ratios at Re=45,000; top: p/djet=3; center: p/djet=4.5; bottom: p/djet=6

Grahic Jump Location
Fig. 11

Line-averaged Nusselt numbers on wall C (left) and wall D (right) for different p/djet at various Reynolds numbers; top: Re=10,000; center: Re=45,000; bottom: Re=75,000

Grahic Jump Location
Fig. 12

Experimental results: local Nusselt number ratios at Re=45,000; top: cylindrical bores; center: conical bores I; bottom: conical bores II

Grahic Jump Location
Fig. 13

Numerical results: local Nusselt number ratios at Re=45,000; top: cylindrical bores; center: conical bores I; bottom: conical bores II

Grahic Jump Location
Fig. 14

Line-averaged Nusselt numbers for different bore shapes at Re=45,000; left: wall C; right: wall D

Grahic Jump Location
Fig. 15

Correlation between the jet shear layer and the location of maximum Nusselt number; left column: jet A1; right column: jet A2; top: cylindrical bores; center: conical bores I; bottom: conical bores II

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In