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Numerical study of the flow past an axial turbine stator casing and perspectives for its management

conference contribution
posted on 15.06.2017, 10:52 by Hakim K. T. Kadhim, Aldo Rona, Hayder M. B. Obaida, J. Paul Gostelow
The interaction of secondary flow with the main passage flow results in entropy generation; this accounts for considerable losses in turbomachines. Low aspect ratio blades in an axial turbine lead to a high degree of secondary flow losses. A particular interest is the reduction in secondary flow strength at the turbine casing, which adversely affects the turbine performance. This paper presents a selective review of effective techniques for improving the performance of axial turbines by turbine end wall modifications. This encompasses the use of axisymmetric and non-axisymmetric end wall contouring and the use of fences. Specific attention is given to non-axisymmetric end walls and to their effect on secondary flow losses. A baseline three-dimensional steady RANS k-ω SST model, with axisymmetric walls, is validated against experimental measurements from the Institute of Jet Propulsion and Turbomachinery at the Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Germany, with comparative solutions generated by ANSYS Fluent and OpenFOAM. The predicted performance of the stator passage with an axisymmetric casing is compared with that from using a contoured casing with a groove designed using the Beta distribution function for guiding the groove shape. The prediction of a reduced total pressure loss coefficient with the application of the contoured casing supports the groove design approach based on the natural path of the secondary flow features. This work also provided an automated workflow process, linking surface definition in MATLAB, meshing in ICEM CFD, and flow solving and post-processing OpenFOAM. This has generated a casing contouring design tool with a good portability to industry, to design and optimize new turbine blade passages.

History

Citation

Proceedings of ASME Turbo Expo 2017: Turbine Technical Conference and Exposition IGTI 2017, 2017, pp. 1-13

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Engineering

Source

ASME Turbo Expo 2017: Turbine Technical Conference and Exposition, Charlotte, NC, USA

Version

AM (Accepted Manuscript)

Published in

Proceedings of ASME Turbo Expo 2017: Turbine Technical Conference and Exposition IGTI 2017

Publisher

American Society of Mechanical Engieers ASME

isbn

978-0-7918-5079-4

Acceptance date

02/03/2017

Copyright date

2017

Publisher version

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2649610

Notes

The file associated with this record is under a permanent embargo in accordance with the publisher's policy. The full text may be available through the publisher links provided above.

Temporal coverage: start date

25/06/2017

Temporal coverage: end date

30/06/2017

Language

en