Desensitization of axial compressor performance and stall margin to tip clearance gap increase
The degradation in performance and operating envelope of aero-engines with age and during critical transient operating conditions such as take-off is a well-known phenomenon. It is mainly caused by the increase in size of the tiny gap between the tip of the compressor rotor blades and the shroud, called tip clearance, from wear and/or shroud thermal expansion, which results in a drop of compressor pressure rise, efficiency and safety margin against aerodynamic instabilities. Two recent doctoral projects at École Polytechnique de Montréal carried out with numerical simulations on a theoretical axial compressor rotor proposed an explanation for this phenomenon and corrective design strategies. A subsequent project applied these strategies to design and simulate a casing treatment and revised rotor to reduce the performance and stall margin sensitivity of a challenging transonic aero-engine axial compressor stage while in parallel modifying a test rig to test these designs for this compressor stage. "TO BE CONT'D"