Session: 28-03 Blade-Tip/Casing Contact

Paper Number: 123911

123911 - Validation of the Numerical Simulation of Rotor/Stator Interactions in Aircraft Engine Low-Pressure Compressors 

In today's turbomachinery, even the slightest gain in compressor performance can translate into higher efficiency and reduced fuel consumption – both of which are highly sought by customers. To achieve better pressure ratios between compressor stages, gas turbines’ designers must minimize aerodynamic losses by preventing tip leakage flows.

A preferred approach is to close the running gaps between the blades and casing by coating the casing with an abradable liner. However, any radial deflection could potentially lead to a failure scenario induced by a structural contact phenomenon between the rotating and fixed parts of the engine. Referred to as rotor/stator interactions, these interactions are difficult to account for during the design phase due to their complexity. Indeed, commercial software packages are ill-suited for the task, and prohibitive costs involved make it unlikely to set up a test rig.

To gain a deeper understanding of rotor/stator interactions, Safran group and Polytechnique Montréal jointly developed a predictive numerical tool to reproduce a blade vibration behavior as it undergoes structural contacts. This article presents the most extensive validation of this numerical tool to date: numerous simulations are carried out and compared to experimental results obtained with different types of blades and abradable liners. The parameters of the numerical simulation are first calibrated with respect to the experimental results related to a single blade of reference. Simulations are then run blindly for other blade geometries across a large range of rotational speeds. Finally, numerical results are thoroughly validated with respect to experimental data. This work also provided an opportunity to introduce an innovative cut-off criterion, based on the maximum allowable yield strength of the material, to delimit the scope of validity of the simulations.

Considering the fairly low computation times required to numerically predict a contact scenario, this numerical tool could be used in early development stages to discriminate against blade designs with respect to their ability to withstand repetitive contacts and thus, ensure, more reliable turbomachines.

Presenting Author: Isabelle Favretti Polytechnique Montréal

Presenting Author Biography: Graduated in 2020 from a bachelor in aerospace engineering from Polytechnique Montréal with a semester spent as an exchange student at Tohoku University, Japan. Presented with success a master degree in aerospace engineering at Polytechnique Montréal in April, 2021. Her expertise resides in non linear vibrations, structural contacts and mechanical integrity of rotor blades for aerospace and industrial applications.

Authors:

Isabelle Favretti Polytechnique Montréal
Louis Roux Safran Aero Boosters
Alain Batailly Polytechnique Montréal