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Journal of Thermal Science

, Volume 25, Issue 1, pp 32–42 | Cite as

Combined experimental and numerical investigations on the roughness effects on the aerodynamic performances of LPT blades

  • Marco Berrino
  • Fabio Bigoni
  • Daniele Simoni
  • Matteo Giovannini
  • Michele Marconcini
  • Roberto Pacciani
  • Francesco Bertini
Article
  • 146 Downloads

Abstract

The aerodynamic performance of a high-load low-pressure turbine blade cascade has been analyzed for three different distributed surface roughness levels (Ra) for steady and unsteady inflows. Results from CFD simulations and experiments are presented for two different Reynolds numbers (300000 and 70000 representative of take-off and cruise conditions, respectively) in order to evaluate the roughness effects for two typical operating conditions.

Computational fluid dynamics has been used to support and interpret experimental results, analyzing in detail the flow field on the blade surface and evaluating the non-dimensional local roughness parameters, further contributing to understand how and where roughness have some influence on the aerodynamic performance of the blade. The total pressure distributions in the wake region have been measured by means of a five-hole miniaturized pressure probe for the different flow conditions, allowing the evaluation of profile losses and of their dependence on the surface finish, as well as a direct comparison with the simulations.

Results reported in the paper clearly highlight that only at the highest Reynolds number tested (Re=300000) surface roughness have some influence on the blade performance, both for steady and unsteady incoming flows. In this flow condition profile losses grow as the surface roughness increases, while no appreciable variations have been found at the lowest Reynolds number. The boundary layer evolution and the wake structure have shown that this trend is due to a thickening of the suction side boundary layer associated to an anticipation of transition process. On the other side, no effects have been observed on the pressure side boundary layer.

Keywords

low-pressure turbine high-load profile roughness unsteady inflow CFD 

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Copyright information

© Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Marco Berrino
    • 1
  • Fabio Bigoni
    • 1
  • Daniele Simoni
    • 1
  • Matteo Giovannini
    • 2
  • Michele Marconcini
    • 2
  • Roberto Pacciani
    • 2
  • Francesco Bertini
    • 3
  1. 1.DIMEUniversitá di GenovaGenovaItaly
  2. 2.DIEFUniversitá di FirenzeFirenzeItaly
  3. 3.GE Avio R&DRivalta (TO)Italy

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