0
RESEARCH PAPERS

Unsteady Wake Over a Linear Turbine Blade Cascade With Air and CO2 Film Injection: Part II—Effect on Film Effectiveness and Heat Transfer Distributions

[+] Author and Article Information
A. B. Mehendale, J.-C. Han, S. Ou

Department of Mechanical Engineering, Turbine Heat Transfer Laboratory, Texas A&M University, College Station, TX 77843

C. P. Lee

Turbine Aero & Cooling Design, General Electric—Aircraft Engines, Cincinnati, OH 45215

J. Turbomach 116(4), 730-737 (Oct 01, 1994) (8 pages) doi:10.1115/1.2929466 History: Received March 01, 1993; Online June 09, 2008

Abstract

The effect of unsteady wake flow and air (D.R. = 0.97) or CO2 (D.R. = 1.48) film injection on blade film effectiveness and heat transfer distributions was experimentally determined. A spoked wheel type wake generator produced the unsteady wake. Experiments were performed on a five-airfoil linear cascade in a low-speed wind tunnel at the chord Reynolds number of 3 × 105 for the no wake case and at the wake Strouhal numbers of 0.1 and 0.3. A model turbine blade with several rows of film holes on its leading edge, and pressure and suction surfaces ( −0.2<X/C< 0.4) was used. Results show that the blowing ratios of 1.2 and 0.8 provide the best film effectiveness over most of the blade surface for CO2 and air injections, respectively. An increase in the wake Strouhal number causes a decrease in film effectiveness over most of the blade surface for both density ratio injectants and at all blowing ratios. On the pressure surface, CO2 injection provides higher film effectiveness than air injection at the blowing ratio of 1.2; however, this trend is reversed at the blowing ratio of 0.8. On the suction surface, CO2 injection provides higher film effectiveness than air injection at the blowing ratio of 1.2; however, this trend is reversed at the blowing ratio of 0.4. Co2 injection provides lower heat loads than air injection at the blowing ratio of 1.2; however, this trend is reversed at the blowing ratio of 0.4. Heat load ratios under unsteady wake conditions are lower than the no wake case. For an actual gas turbine blade, since the blowing ratios can be greater than 1.2 and the density ratios can be up to 2.0, a higher density ratio coolant may provide lower heat load ratios under unsteady wake conditions.

Copyright © 1994 by The American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Related

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