Faculté des Sciences appliquées
Faculté des Sciences appliquées

Evaluation of industrial practices for the prediction of blade flutter in a modern compressor

Piret, Axel ULiège
Promotor(s) : Terrapon, Vincent ULiège
Date of defense : 9-Sep-2019/10-Sep-2019 • Permalink :
Title : Evaluation of industrial practices for the prediction of blade flutter in a modern compressor
Translated title : [fr] Évaluation de pratiques industrielles pour la prédiction du flottement d'une pale de compresseur moderne
Author : Piret, Axel ULiège
Date of defense  : 9-Sep-2019/10-Sep-2019
Advisor(s) : Terrapon, Vincent ULiège
Committee's member(s) : Dimitriadis, Grigorios ULiège
Habotte, Nicolas 
Language : English
Number of pages : 105
Keywords : [en] Blade flutter
[en] Weak coupling
[en] Compressor aeroelasticity
[en] Experimental validation
[en] CFD
Discipline(s) : Engineering, computing & technology > Aerospace & aeronautics engineering
Funders : Safran Aero Boosters
Target public : Researchers
Professionals of domain
Institution(s) : Université de Liège, Liège, Belgique
Degree: Master en ingénieur civil en aérospatiale, à finalité spécialisée en "aerospace engineering"
Faculty: Master thesis of the Faculté des Sciences appliquées


[en] Blade flutter may induce high cycle fatigue or sudden blade loss and must be
avoided. Flutter prediction constitutes a rather recent activity at Safran Aero
Boosters (SAB), and the current numerical modelling practices of the company
require validation. The thesis presents an evaluation of these practices against
experimental flutter results recorded during the test campaign of a low-pressure
compressor designed at SAB.
Using unsteady pressure signals, flutter of the first rotoric blade row is identified at 50% of the nominal rotation speed near the surge line. The instability
is shown to occur on the first bending mode presenting ten nodal diameters.
Extensive test data allow to establish a data-matched throughflow representation of the experimented flow, using complementary information from RANS
calculations. The latter presenting considerable discrepancies with respect to
the test data, matching requires the introduction of artificial corrections in the
throughflow representation.
This representation allows to establish representative boundary conditions
for the subsequent URANS flutter calculations. A weakly coupled approach
is adopted, whereby an harmonic blade motion is prescribed with the studied
mode. Phase-shifted boundary conditions allow to reduce the domain to a single passage. Stability is inferred by computing the work done by aerodynamic
forces over a vibration period.
The present calculations do not agree with the experiments: the studied
mode is predicted stable. SAB’s current practices appear thus unable to predict flutter in near stall conditions. They however enable to highlight the
stabilising effect of the motion induced incidence. Blade-to-blade interactions
through strong, unsteady tip vortices appear to be the main (if not unique)
destabilising mechanism. The lacking quality of the present calculations is believed to originate in part in the mediocre accuracy of the k−" RANS model in
separated flow regions and possibly in an inaccurate prediction of the unsteady
tip vortices. The dependency of the results on numerical parameters may also
be strong. A sensitivity analysis could constitute a basis for future work.



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  • Piret, Axel ULiège Université de Liège > Master ingé. civ. aérospat., à fin.


Committee's member(s)

  • Dimitriadis, Grigorios ULiège Université de Liège - ULiège > Département d'aérospatiale et mécanique > Interactions Fluide-Structure - Aérodynamique expérimentale
    ORBi View his publications on ORBi
  • Habotte, Nicolas Safran Aero Boosters > Direction Technique > Centre de compétence aérodynamique
  • Total number of views 72
  • Total number of downloads 0

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