Full Content is available to subscribers

Subscribe/Learn More  >

Aerothermal Performance of Shroudless Turbine Blade Tips With Effects of Relative Casing Motion

[+] Author Affiliations
A. S. Virdi, Q. Zhang, L. He

University of Oxford, Oxford, UK

H. D. Li, R. Hunsley

Rolls-Royce plc, Bristol, UK

Paper No. TBTS2013-2021, pp. V001T02A003; 12 pages
  • ASME 2013 Turbine Blade Tip Symposium
  • ASME 2013 Turbine Blade Tip Symposium
  • Hamburg, Germany, September 30–October 3, 2013
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-5607-9
  • Copyright © 2013 by Rolls-Royce plc


Recent work has indicated qualitatively different heat transfer characteristics between a transonic blade tip and a subsonic one. High resolution experimental data can be acquired for blade tip heat transfer research using a high speed linear cascade. While recognising an important role played by the cascade tests in validating computational models at the same conditions, some questions arise in relation to the effects of relative casing motion:

1) Does the relative casing movement change the main flow physics influencing the blade tip aerothermal performance?

2) Can a cascade set up with stationary casing wall rank different designs?

3) How do the effects of the casing motion depend on tip design configurations?

A combined experimental and CFD study on several high pressure blade tip configurations is conducted to address these issues.

Firstly, extensive experimental tests with aerodynamic loss and heat transfer measurement in a high speed linear cascade have been carried out for a squealer tip configuration at engine representative aerodynamic conditions. A systematic validation of the CFD solver (Rolls-Royce HYDRA) is presented, which serves as a basis for the computational analyses of the effects of the relative casing motion.

Two tip configurations (squealer and flat tip) at three tip gaps (0.5%, 1.0%, 1.5% span) are analysed. The main aerodynamic impact of the casing motion is seen to promote the passage vortex, which consequently supresses the pitchwise reach of the tip leakage vortex. Inside the tip gap, the behaviour is dominated by the extra wall friction in relation of the inertia of the bulk fluid through the gap. As such, the moving casing effect is particularly strong for the flat tip at a small tip gap. For the large and medium tip gaps, both stationary and moving casing results are shown to consistently capture the trends in overall aerothermal performances.

The present results confirm that even with relative casing motion, there is still a significant portion of transonic flow over a blade tip. For both the stationary and moving casing cases, the gap dependence of the over-tip heat transfer shows opposite trends for the transonic and subsonic regions respectively. The gap dependence of the blade tip heat transfer is shown to be clearly dependent on tip geometry configurations, as the bulk flow in a squealer cavity is subsonic regardless of the tip gap size, whilst the local flow state over a flat tip is much more responsive to the change of gap size.

Copyright © 2013 by Rolls-Royce plc



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

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 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