Full Content is available to subscribers

Subscribe/Learn More  >

Improvement of Flow Conditions for the Stages Subsequent to Extraction Modules in Industrial Steam Turbines

[+] Author Affiliations
Andreas Schramm, Tim Müller, Ronald Mailach

Ruhr-Universität Bochum, Bochum, Germany

Thomas Polklas, Oliver Brunn

MAN Diesel & Turbo SE, Oberhausen, Germany

Paper No. GT2014-25390, pp. V01BT27A008; 10 pages
  • ASME Turbo Expo 2014: Turbine Technical Conference and Exposition
  • Volume 1B: Marine; Microturbines, Turbochargers and Small Turbomachines; Steam Turbines
  • Düsseldorf, Germany, June 16–20, 2014
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-4558-5
  • Copyright © 2014 by ASME


Industrial steam turbines are applied for power generation as well as drive for turbo-compressors. They combine a high level of operational flexibility with highest reliability. Especially in the field of process technology they provide process heat on a certain enthalpy level for other industrial applications. Modular design concepts are used to meet these various requirements like admission or extraction of large steam quantities. Extraction modules use valves to control the amount of steam extracted from the turbine expansion path at constant steam parameters.

While extraction steam is taken from the turbine through an outlet flange, the remaining steam passes valves and downstream diffusers, flows into an annular inner casing and finally escapes through the subsequent stages. Depending on the valve lift, different flow separations can occur around the valves, resulting in unsteady transonic jets. Due to the compact and asymmetric design of the inner casing the flow into the subsequent stages is strongly disturbed. Hence, strong unsteady mechanical blade loading can occur in addition to efficiency loss.

The current work focusses on the improvement of the flow conditions in the subsequent stage. Experimental results are applied to quantify the viability of the used 3D RANS CFD-solver (ANSYS CFX 14) for these numerical investigations. Compared with the experiment, the distribution of pressure, velocity and incidence angle are well predicted by the numerical code. It is evident that the unsteady transonic jets emerging around the valves have a major influence on the distribution of the parameters considered. Thus, to quantify the impact of a modified inlet chamber design, it is sufficient to simulate the domain starting from the valves.

The influence of different design modifications on the flow parameters in comparison with the base design is discussed in detail in an extensive study. The results clarify that horizontal and vertical valve positions, as well as thorough contouring of the radial-axial deflection have a strong influence on the distribution of pressure, mass flux and incidence angle. Hence, in this contribution combinations of the most beneficial modifications are investigated numerically and compared with the base design.

Copyright © 2014 by ASME



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