0
INVITED PAPERS

Numerical Modeling of Heat Transfer and Pressure Losses for an Uncooled Gas Turbine Blade Tip: Effect of Tip Clearance and Tip Geometry

[+] Author and Article Information
Lamyaa A. El-Gabry

Department of Mechanical Engineering, American University in Cairo, Cairo, Egypt 11511lelgabry@aucegypt.edu

J. Thermal Sci. Eng. Appl 1(2), 022005 (Nov 18, 2009) (10 pages) doi:10.1115/1.4000547 History: Received July 29, 2009; Revised October 20, 2009; Published November 18, 2009; Online November 18, 2009

A computational study has been performed to predict the heat transfer distribution on the blade tip surface for a representative gas turbine first stage blade. Computational fluid dynamics (CFD) predictions of blade tip heat transfer are compared with test measurements taken in a linear cascade, when available. The blade geometry has an inlet Mach number of 0.3 and an exit Mach number of 0.75, pressure ratio of 1.5, exit Reynolds number based on axial chord of 2.57×106, and total turning of 110 deg. Three blade tip configurations were considered; a flat tip, a full perimeter squealer, and an offset squealer where the rim is offset to the interior of the tip perimeter. These three tip geometries were modeled at three tip clearances of 1.25%, 2.0%, and 2.75% of the blade span. The tip heat transfer results of the numerical models agree well with data. For the case in which side-by-side comparison with test measurements in the open literature is possible, the magnitude of the heat transfer coefficient in the “sweet spot” matches data exactly and shows 20–50% better agreement with experiment than prior CFD predictions of this same case.

Copyright © 2009 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Blade tip cascade test facility, courtesy of Bunker (4)

Grahic Jump Location
Figure 2

Airfoil and shroud definition, courtesy of Bunker (4)

Grahic Jump Location
Figure 3

Blade tip configurations: (a) flat tip, (b) full perimeter squealer, and (c) offset squealer

Grahic Jump Location
Figure 5

Effect of tip clearance on neartip pressure distribution: (a) flat tip, (b) full perimeter squealer, and (c) offset squealer

Grahic Jump Location
Figure 6

Effect of tip geometry on neartip pressure distribution: (a) tip gap=1.25% span, (b) tip gap=2% span, and (c) tip gap=2.75% span

Grahic Jump Location
Figure 7

Flat tip heat transfer coefficients (W/m2/K)

Grahic Jump Location
Figure 8

Full perimeter squealer tip heat transfer coefficients (W/m2/K)

Grahic Jump Location
Figure 9

Offset squealer tip heat transfer coefficients (W/m2/K)

Grahic Jump Location
Figure 10

Sharp edged blade tip heat transfer coefficient (W/m2/K) for clearance 2% span, courtesy of Ameri (12)

Grahic Jump Location
Figure 11

Flow streamlines over full perimeter squealer tip for (a) 1.25% and (b) 2.75% span tip gaps

Grahic Jump Location
Figure 12

Effect of tip geometry and tip gap on overall blade pressure drop

Grahic Jump Location
Figure 13

Effects of tip geometry and tip gap on tip leakage flow

Grahic Jump Location
Figure 14

Effect of blade tip geometry on normalized pressure distribution (PT/PTinlet) for 2% tip clearance

Grahic Jump Location
Figure 15

Effect of tip gap clearance on normalized pressure distribution (PT/PTinlet) for offset squealer tip geometry

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