Investigation of experimental and numerical methods, and analysis of stator clocking and instabilities in a high-speed multistage compressor
- D. VOGT - Professeur, Université de Stuttgart, Rapporteur
- P. ZUNINO - Professeur, Université de Gênes, Rapporteur
- I. TRÉBINJAC - Professeur, Ecole centrale de Lyon, Examinatrice
- M. DUMAS - Ingénieur, Safran Aircraft Engines, Examinateur
- X. OTTAVY - Chargé de Recherche, Ecole centrale de Lyon, Directeur de thèse
This thesis presents experimental and numerical work that aim at the deep understanding of the flow field in the 3.5 stages high-speed axial compressor CREATE (installed on ECL-B2). This work focuses on three major objectives : Firstly, a global description of the flow field with an identification of limitations to the used exploration methods ; Secondly, the characterization of the effect of stator-stator clocking in a high-speed compressor ; Thirdly, the identification of instabilities arising at low mass flow rates for confirming studies on low-speed compressors and giving new insights.
Firstly, this work demonstrates that the experimental and numerical flow field exploration methods are challenged at certain locations in the compressor. The identification will initiate further development of the methods. Secondly, the investigation of the stator clocking reveals only a small global effect within the measurement uncertainty band. Several contributions to the weak effect of clocking are identified by analysis of the flow structure transport. Local possible positive and negative effects of clocking are demonstrated to be almost in balance. Thirdly, the arising instabilities depend on the operating point and flow field exploration methods in this compressor. That allows the detailed characterization of rotating instabilities and a spike type stall inception in the high-speed compressor environment. New insights into the stable behavior and periodicity of the measured rotating instability are derived contrary to the unstable behavior suggested by the naming and literature.
Instantaneous entropy map showing rotating disturbance in black circles at 82% span-height