Fluid Mechanics and Acoustics Laboratory - UMR 5509

LMFA - UMR 5509
Laboratoire de Mécanique des Fluides et d’Acoustique

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Home > Teams > Turbulence & Instabilities > Casual seminar > Past seminars > Séminaires 2016

Annabelle Zhang

Étude expérimentale des instabilités de l’écoulement dans un compresseur axial basse vitesse

Jeudi 26 mai 2016 13h, UCBL Bât Omega

Étude expérimentale des instabilités de l'écoulement dans un compresseur axial basse vitesse

Flow instability in turbomachinery is caused by spontaneous growth of small perturbations of the nominal flow in compression system, which can lead to degradation in performance, large-amplitude oscillations, and even structural damages. Instabilities of linear origin (growth of small disturbances) correspond to normal modes of the flow whose growth/decay rate passes through zero at the stability threshold. The aim of Calypso project is to develop experimental techniques based on active, impulsive forcing (e.g. compressed air impulses) to characterize the precursors of instability, similar in principle to tapping an elastic structure to identify the normal mode frequencies and spatial structure (a technique widely used by structural engineers). This should provide us an improved understanding of the onset of instability and direct input to theoretical models. The acoustical phenomena (due to the inlet and outlet ducts) near the instability threshold will be analyzed at the same time