0
TECHNICAL PAPERS

Experimental and Numerical Study of Mass/Heat Transfer on an Airfoil Trailing-Edge Slots and Lands

[+] Author and Article Information
M. Cakan

Mechanical Engineering Department, Istanbul Technical University, 34439 Istanbul, TurkeyMechanical and Industrial Engineering Department, Northeastern University, Boston, MA 02115

M. E. Taslim

Mechanical Engineering Department, Istanbul Technical University, 34439 Istanbul, Turkeym.taslim@neu.eduMechanical and Industrial Engineering Department, Northeastern University, Boston, MA 02115m.taslim@neu.edu

J. Turbomach 129(2), 281-293 (Sep 04, 2006) (13 pages) doi:10.1115/1.2436898 History: Received July 05, 2006; Revised September 04, 2006

Proper cooling of the airfoil trailing edge is imperative in gas turbine designs since this area is often one of the life limiting areas of an airfoil. A common method of providing thermal protection to an airfoil trailing edge is by injecting a film of cooling air through slots located on the airfoil pressure side near the trailing edge, thereby providing a cooling buffer between the hot mainstream gas and the airfoil surface. In the conventional designs, at the breakout plane, a series of slots open to expanding tapered grooves in between the tapered lands and run the cooling air through the grooves to protect the trailing edge surface. In this study, naphthalene sublimation technique was used to measure area averaged mass/heat transfer coefficients downstream of the breakout plane on the slot and on the land surfaces. Three slot geometries were tested: (a) a baseline case simulating a typical conventional slot and land design; (b) the same geometry with a sudden outward step at the breakout plane around the opening; and (c) the sudden step was moved one-third away from the breakout plane in the slot. Mass/heat transfer results were compared for these slots geometries for a range of blowing ratios [M=(ρu)s(ρu)m] from 0 to 2. For the numerical investigation, a pressure-correction based, multiblock, multigrid, unstructured/adaptive commercial software was used in this investigation. Several turbulence models including the standard high Reynolds number k-ε turbulence model in conjunction with the generalized wall function were used for turbulence closure. The applied thermal boundary conditions to the computational fluid dynamics (CFD) models matched the test boundary conditions. Effects of a sudden downward step (Coanda) in the slot on mass/heat transfer coefficients on the slot and on the land surfaces were compared both experimentally and numerically.

Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 7

Sherwood number variation on the land surface inside the slot downstream of the breakout plane, baseline geometry

Grahic Jump Location
Figure 8

Sherwood number variation on the land top surface downstream of the breakout plane, baseline geometry

Grahic Jump Location
Figure 9

Sherwood number variation on the slot floor downstream of the breakout plane, Geometry 2 (step at the breakout plane)

Grahic Jump Location
Figure 16

Area-weighted average Sherwood number variation versus blowing ratio (M) on the lip surface

Grahic Jump Location
Figure 17

Area-weighted average Sherwood number variation versus blowing ratio (M) on the step surfaces

Grahic Jump Location
Figure 18

Comparison between the experimental and numerical results for a blowing ratio of 0.82

Grahic Jump Location
Figure 19

Comparison between the experimental and numerical results for on the lip surface

Grahic Jump Location
Figure 20

Representative numerical heat transfer coefficient variation on the slot and land surfaces

Grahic Jump Location
Figure 21

Representative numerical temperature variation on the slot and land surfaces

Grahic Jump Location
Figure 1

Schematics of the test section

Grahic Jump Location
Figure 2

Schematics of the end piece for Geometry 3

Grahic Jump Location
Figure 3

Details of the end piece for Geometry 2

Grahic Jump Location
Figure 4

Details of the naphthalene surfaces

Grahic Jump Location
Figure 5

Typical mesh arrangement around the computational domain periphery

Grahic Jump Location
Figure 6

Sherwood number variation on the slot floor downstream of the breakout plane, baseline geometry

Grahic Jump Location
Figure 10

Sherwood number variation on the land surface inside the slot downstream of the breakout plane, Geometry 2 (step at the breakout plane)

Grahic Jump Location
Figure 11

Sherwood number variation on the land top surface downstream of the breakout plane, Geometry 2 (step at the breakout plane)

Grahic Jump Location
Figure 12

Sherwood number variation on the slot floor downstream of the breakout plane, Geometry 3 (step at 1∕3 of slot axial length)

Grahic Jump Location
Figure 13

Sherwood number variation on the land surface inside the slot downstream of the breakout plane, Geometry 3 (step at 1∕3 of slot axial length)

Grahic Jump Location
Figure 14

Sherwood number variation on the land top surface downstream of the breakout plane, Geometry 3 (step at 1∕3 of slot axial length)

Grahic Jump Location
Figure 15

Area-weighted average Sherwood number variation versus blowing ratio (M) for the three slot geometries and two mainstream Reynolds numbers

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.

Related Journal Articles
Related eBook Content
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