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dc.contributor.author
Schüpbach, Peter
dc.contributor.author
Abhari, Reza S.
dc.contributor.author
Rose, Martin G.
dc.contributor.author
Germain, Thomas
dc.contributor.author
Raab, Irene
dc.contributor.author
Gier, Jochen
dc.date.accessioned
2022-10-03T11:37:11Z
dc.date.available
2017-06-08T21:08:18Z
dc.date.available
2022-10-03T11:37:11Z
dc.date.issued
2008
dc.identifier.isbn
978-0-7918-3824-2
en_US
dc.identifier.other
10.1115/GT2008-50470
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/13773
dc.description.abstract
This paper is the second part of a two part paper that reports on the improvement of efficiency of a one-and-half stage high work axial flow turbine. The first part covered the design of the endwall profiling as well as a comparison with steady probe data, this part covers the analysis of the time-resolved flow physics. The focus is on the time-resolved flow physics that lead to a total-to-total stage efficiency improvement of Δηtt = 1.0% ± 0.4%. The investigated geometry is a model of a high work (Δh/U2 = 2.36), axial shroudless HP turbine. The time-resolved measurements have been acquired upstream and downstream of the rotor using a Fast Response Aerodynamic Probe (FRAP). The paper contains a detailed analysis of the secondary flow field that is changed between the axisymmetric and the non-axisymmetric endwall profiling cases. The flowfield at exit of the first stator is improved considerably due to non-axisymmetric endwall profiling and results in reduced secondary flow and a reduction of loss at both hub and tip, as well as a reduced trailing shed vorticity. The rotor has reduced losses and a reduction of secondary flows mainly at the hub. At the rotor exit the flow field with non-axisymmetric endwalls is more homogenous due to the reduction of secondary flows in the two rows upstream of the measurement plane. This confirms that non-axisymmetric endwall profiling is an effective tool for reducing secondary losses in axial turbines. Using a frozen flow assumption the time-resolved data is used to estimate the axial velocity gradients, which are then used to evaluate the streamwise vorticity and dissipation. The non-axisymmetric endwall profiling of the first nozzle guide vane show reductions of dissipation and streamwise vorticity due to reduced trailing shed vorticity. This smaller vorticity explains the reduction of loss at mid-span, which is shown in the first part of the two part paper. This leads to the conclusion that non-axisymmetric endwall profiling also has the potential of reducing trailing shed vorticity.
en_US
dc.language.iso
en
en_US
dc.publisher
American Society of Mechanical Engineers
en_US
dc.title
Improving Efficiency of a High Work Turbine Using Non-Axisymmetric Endwalls: Part II—Time-Resolved Flow Physics
en_US
dc.type
Conference Paper
dc.date.published
2009-08-03
ethz.book.title
Proceedings of ASME Turbo Expo 2008
en_US
ethz.journal.volume
6 Part B
en_US
ethz.pages.start
1121
en_US
ethz.pages.end
1133
en_US
ethz.event
ASME Turbo Expo 2008: Power for Land, Sea, and Air (GT 2008)
en_US
ethz.event.location
Berlin, Germany
en_US
ethz.event.date
June 9-13, 2008
en_US
ethz.notes
GT2008-50470
en_US
ethz.publication.place
New York, NY
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02668 - Inst. f. Energie- und Verfahrenstechnik / Inst. Energy and Process Engineering::03548 - Abhari, Reza S. / Abhari, Reza S.
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02668 - Inst. f. Energie- und Verfahrenstechnik / Inst. Energy and Process Engineering::03548 - Abhari, Reza S. / Abhari, Reza S.
ethz.date.deposited
2017-06-08T21:08:28Z
ethz.source
ECIT
ethz.identifier.importid
imp59364c3152a3995457
ethz.ecitpid
pub:25261
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2017-07-12T18:18:09Z
ethz.rosetta.lastUpdated
2021-02-14T05:33:50Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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