The Flow in a Second Stage Nozzle of a Low Speed Axial Turbine and its Effect on Tip Clearance Loss Development PUBLIC ACCESS

[+] Author Affiliations
G. Morphis, J. P. Bindon

University of Natal, Durban, South Africa

Paper No. 94-GT-145, pp. V001T01A055; 8 pages
  • ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition
  • Volume 1: Turbomachinery
  • The Hague, Netherlands, June 13–16, 1994
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-7883-5
  • Copyright © 1994 by ASME


The flow field in a one and a half stage low speed axial turbine with varying levels of rotor tip clearance was measured in order to compare the behaviour of the second nozzle with the first and to identify the manner in which second nozzle responds to the complex tip clearance dependent flow presented to it and completes the formation of tip clearance loss.

The tangentially averaged flow relative to the rotor blade in the tip clearance region was found to differ radically from that found in cascade and is not underturned with a high axial velocity. There is evidence rather of overturning caused by secondary flow. The axial velocity follows an almost normal endwall boundary layer pattern with almost no leakage jet effect. The cascade tip clearance model is therefore not accurate.

The reduction in second stage nozzle loss was shown to occur near the hub and tip which confirms that it is probably a reduction in secondary flow loss. The nozzle exit loss contours showed that leakage suppressed the formation of the classical secondary flow pattern and that a new tip clearance related loss phenomena exists on the suction surface.

The second stage nozzle reduced hub endwall boundary layer below that of both the first nozzle and that behind the rotor. It also rectified secondary and tip clearance flows to such a degree that a second stage rotor would experience no greater flow distortion than the first stage rotor.

Radial flow angles behind the second stage nozzle were much smaller than found in a previous study with low aspect ratio un-twisted blades.

Copyright © 1994 by ASME
This article is only available in the PDF format.



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