0

Full Content is available to subscribers

Subscribe/Learn More  >

Calculations of Cooled Turbine Efficiency

[+] Author Affiliations
J. H. Horlock

Cambridge University, Cambridge, UK

Leonardo Torbidoni

Ansaldo Energia, Genoa, Italy

Paper No. GT2006-90424, pp. 127-132; 6 pages
doi:10.1115/GT2006-90424
From:
  • ASME Turbo Expo 2006: Power for Land, Sea, and Air
  • Volume 4: Cycle Innovations; Electric Power; Industrial and Cogeneration; Manufacturing Materials and Metallurgy
  • Barcelona, Spain, May 8–11, 2006
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 0-7918-4239-8
  • Copyright © 2006 by ASME

abstract

The efficiency of a cooled turbine stage has been discussed in the literature. All proposed definitions compare the actual power output with an ideal output, which has to be determined; but usually one of two definitions has been used by turbine designers. In the first, the so-called Hartsel efficiency, the mainstream gas flow and the various coolant flows to rotor and stator are assumed to expand separately and isentropically to the back pressure. In the second it is assumed that these flows mix at constant (mainstream) gas pressure before expanding isentropically (sometimes the rotor coolant flow is ignored in this definition). More recently it has been suggested that a thermodynamically sounder definition is one in which the gas and coolant flows mix reversibly and adiabatically before isentropic expansion to the back pressure. In the current paper these three efficiencies are compared, for a typical stage — the first cooled stage of a multistage industrial gas turbine. It is shown that all the efficiencies fall more or less linearly with increase of the fractional (total) coolant flow. It is also shown that the new definition of efficiency gives values considerably lower than the other two efficiencies, which are more widely used at present. Finally, the various irreversibilities associated with the flow through a cooled turbine are calculated. Although all these irreversibilities increase with the fractional coolant flow, it is shown that the “thermal” irreversibility associated with film cooling is higher than the other irreversibilities at large fractional coolant flow.

Copyright © 2006 by ASME
Topics: Turbines

Figures

Tables

Interactive Graphics

Video

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

NOTE:
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