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@PHDTHESIS{Zimmermann:697625,
      author       = {Zimmermann, Tobias Winfried},
      othercontributors = {Wirsum, Manfred Christian and Vogt, Damian},
      title        = {{A}erodynamic performance of endwall contoured turbine
                      blades considering leakage flow interaction},
      school       = {Rheinisch-Westfälische Technische Hochschule Aachen},
      type         = {Dissertation},
      address      = {Aachen},
      reportid     = {RWTH-2017-07179},
      pages        = {1 Online-Ressource (VIII, 166 Seiten) : Illustrationen,
                      Diagramme},
      year         = {2017},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, Rheinisch-Westfälische Technische
                      Hochschule Aachen, 2017},
      abstract     = {Tangential endwall contouring is intended to improve the
                      blading efficiency in turbomachinery. The present thesis
                      focusses on the influence of leakage flows on the
                      performance of non-axisymmetric endwall contouring in
                      combination with a compound lean turbine blading.All tests
                      were conducted on a 2 stage axial turbine test rig at the
                      Institute of Power Plant Technology, Steam and Gas Turbines
                      (IKDG) of RWTH Aachen University. The test rig is driven
                      with air. Two sealing set-ups are applied to create two
                      different leakage mass flows. Four operating points are
                      investigated that represent the design point as well as
                      overload and partload conditions.The endwall contouring is
                      applied on both hub and tip sides. Three configurations are
                      compared. A baseline design without endwall contouring,
                      contoured stator vanes and non-contoured rotor blades as
                      well as contoured vanes and blades.At first, all
                      configurations are investigated with a negligible leakage
                      flow rate at the casing side. The results show that the vane
                      contoured configuration performs best in stage 1 while the
                      fully contoured set-up loses in efficiency for the design
                      point and in partload compared to the baseline
                      configuration. This trend is flipped in stage 2 as the fully
                      contoured version performs best and the vane contoured
                      configuration loses significantly. This finding suggests
                      that endwall contouring has the potential to increase the
                      efficiency of multi stage turbines.The second focus is put
                      on the interaction of endwall contouring and leakage flow.
                      These investigations show that neither the vane contoured
                      nor the fully contoured set-up show an increased efficiency
                      at any operating point. The trends within the first stage
                      are similar to the measurements with the low amount of
                      leakage flow. In the second stage both contouring designs
                      perform worse than the baseline, leading to the assumption
                      that the change in efficiency is mainly caused by the
                      re-entering leakage mass flow upstream the contouring and
                      not by the flow that enters the cavities in front of the
                      rotor contouring.},
      cin          = {412510},
      ddc          = {620},
      cid          = {$I:(DE-82)412510_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2017-07179},
      url          = {https://publications.rwth-aachen.de/record/697625},
}