Unsteadiness and instabilities in compressors

Theme：Unsteadiness and instabilities in compressors

Speaker：Xavier Ottavy

Time：September 26th 2014, 10:00AM

Venue：Lecture Hall, Aerospace Building

Abstract:

In a compressor stage the unsteadiness is inherent to the flow field. It is generated by the flow structures induced by a row (pressure waves, secondary flows, technological effects…) and propagated both upstream and downstream to the other rows. The Laboratory of fluid Mechanics and Acoustics (LMFA) at Ecole Centrale Lyon in France have conducted studies on several test cases in order to investigate the sources of the unsteadiness. Some low speed experiments as high-speed compressors configurations are studied experimentally and numerically with the aim of highlighting the unsteady effects and their consequences on global performances but also on the onset of instabilities. Detailed investigations of secondary flows and rotor/stator interactions are the subject of this presentation.

Bio:

Education

• 1993 : Graduated from University Claude Bernard Lyon I

• 1994 : D.E.A. (Master degree - Speciality Mechanics) at University Claude Bernard Lyon I

• Dec. 1995 – May 1999 : PhD Thesis at Ecole Centrale de Lyon (Lab. : LMFA)

Successive Positions

• 1994-95 : Scientifique du contingent at ONERA (National center for studies and researches on aerodynamics). Experimental studies on the axial compressor rig ERECA.

• Dec. 1998 - Sep 1999: Research associate at Centrale Lyon Innovation. APPACET European Program: WP concerning the unsteady pressure measurements in a transonic axial compressor (ECL4).

• Oct. 1999 - Nov. 2000 : Research associate at Cambridge University (Whittle Laboratory). Experimental study of the effects of wake-passing unsteadiness over a highly loaded compressor-like flat plate.

• Dec. 2000 - present : Permanent researcher at French National Center for Scientific Research (CNRS section 10, STII); Turbomachinery Team, Fluid Mechanics and Acoustics Laboratory (LMFA UMR CNRS 5509, at Ecole Centrale de Lyon)

Research activities

• Modal approach for rotor/stator interactions in high-speed multistage compressor.

• Instabilities in axial compressors.

• Development of experimental tools for turbomachinery applications: Laser anemometry for measurements in high speed machines, Doppler Global (planar) Velocimetry for academic experiments.

Administrative positions

• Supervisor of the CREATE program (Compressor for Research on Aerodynamic and Technological Effects), tested with the 2MW compressor rig ECL-B2 at LMFA (Industrial Snecma).

• Equipex PHARE : Supervisor of the mutli-physic test rig ECL-B3.

• Co-supervisor of the research field in the Turbomachinery Team of LMFA: “Instabilities and unsteadiness in high speed turbomachines”

• 8th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows at Ecole Centrale de Lyon, July 2007.

• XXII Biannual Symposium on Measurement Techniques in Turbomachinery at Ecole Centrale de Lyon, Sept 2014.

• Supervisor of the Quality Plan for the experiments on the LMFA compressor test rigs.