aeroelastiCs Of faNs anD cOmpressors – CONDOR

The CONDOR project adopts a multidisciplinary approach combining experiments, numerical simulations, and advanced modeling to analyze the aeroelasticity of fans and compressors.

1. Wind Tunnel Experiments and Acoustic Characterization
Wind tunnel tests are conducted to study the interactions between airflow and blade structures. A specialized instrumentation setup, including miniaturized microphones and speakers for acoustic excitation, helps analyze vibratory modes and identify instabilities.

2. High-Fidelity Simulations (CFD and FSI)
Advanced numerical simulations leverage Computational Fluid Dynamics (CFD) and Fluid-Structure Interaction (FSI) techniques. These analyses capture nonlinear vibration effects and explore the mechanisms behind unstable phenomena such as Non-Synchronous Vibrations (NSV) and flutter.

3. Reduced-Order Modeling
A reduced-order model is being developed to predict aeroelastic instabilities while incorporating nonlinear effects and mistuning. This model aims to optimize fan design and propose instability control strategies for next-generation engines.

4. Experimental Validation and Industrial Application
The developed models are compared with experimental results to validate their accuracy and industrial applicability. The project explores solutions such as blade design optimization and casing treatments to mitigate instabilities.

By integrating these approaches, CONDOR aims to deliver innovative simulation and design tools to enhance the reliability and performance of aircraft engines while minimizing their environmental footprint.

The CONDOR project has already achieved significant progress in understanding and controlling aeroelastic instabilities in fans and compressors.

1. Advances in Experimental Studies

A specially designed annular grid equipped with acoustic and vibration sensors has been tested to study acoustic modes and aeroelastic instabilities.
Advanced instrumentation, including a network of speakers and miniaturized microphones, has enabled precise excitation and measurement of blade vibratory modes.
A new test facility with a wind tunnel and airflow conduits has been completed, providing controlled conditions for measurements.

2. Development and Validation of Numerical Models

A complete simulation framework integrating nonlinear vibration effects has been developed.
High-fidelity Computational Fluid Dynamics (CFD) and Fluid-Structure Interaction (FSI) simulations have been conducted to analyze Non-Synchronous Vibrations (NSV).
Initial validation of numerical models has been performed by comparing simulation results with experimental data.

3. Optimization and Reduced-Order Modeling

A reduced-order model has been created to predict aeroelastic instabilities while incorporating mistuning effects.
Design methodologies have been improved to optimize blade aeroelasticity and reduce instability risks.

4. Industrial Impact and Collaboration with Safran

The project led to a strategic shift, replacing variable-pitch fan studies with casing treatment solutions to stabilize airflow in transonic engines.
A methodology for optimizing casing treatments has been developed and tested through advanced numerical simulations.
Knowledge transfer to industry has begun, with promising applications for next-generation aircraft engines.

5. Dissemination and Future Prospects

Project findings have been presented at scientific conferences and integrated into academic publications.
A dedicated workshop on project advancements is planned for 2025, bringing together academic and industry experts.
New research directions are emerging, particularly in optimizing casing treatments and improving simulation models.

With these advancements, CONDOR is contributing to the development of next-generation aircraft engines, enhancing their reliability and performance while minimizing environmental impact.

The CONDOR project opens promising avenues for enhancing aircraft engines by integrating innovative approaches in aeroelasticity and fluid dynamics.

1. Optimization of Models and Simulations

Further improve numerical models to better predict aeroelastic instabilities.
Integrate machine learning techniques to refine simulation accuracy and accelerate computations.
Extend analyses to next-generation engine architectures, particularly Ultra-High Bypass Ratio (UHBR) configurations.

2. Additional Experiments and Validation

Finalize tests on casing treatment and validate its effectiveness on the ECL5 configuration.
Conduct new wind tunnel measurement campaigns to explore additional parameters influencing instabilities.
Compare and refine experimental results with numerical model predictions.

3. Industrial Applications and Technology Transfer

Collaborate with Safran Aircraft Engines to integrate CONDOR’s advancements into future engine designs.
Adapt the developed methodologies to other aircraft engine components to optimize overall robustness.
Explore the potential application of aeroelasticity models in other industries, such as wind energy and gas turbines.

4. Training and Scientific Dissemination

Strengthen the training of young researchers and engineers in aeroelasticity challenges through specialized courses.
Publish project findings in leading scientific journals and present them at international conferences.
Organize an annual workshop bringing together researchers and industry experts to share advancements and foster collaborative innovation.

5. New Research Directions

Investigate fluid-structure interaction effects on advanced composite materials to improve blade design.
Study the impact of extreme environmental conditions (turbulence, thermal variations) on aeroelastic instabilities.
Develop active control strategies to mitigate vibrations in real time and optimize engine performance.

With these perspectives, CONDOR is positioned as a key project for the evolution of aircraft engines, contributing to their reliability, durability, and energy efficiency.

In the first reporting period, no publications were realized, but several are already in preparation, and the first conferences will be held in early 2025.

The transition to climate-neutrality places huge technological challenges on turbomachines, used in aviation propulsion systems. One of the major challenges and current design constraints is the optimisation of flexible rotor blades under high aerodynamic loads. When subject to complex fluid-dynamic forces, rotor blades deform statically and dynamically. This aeroelastic interaction can ultimately cause component failure. The current engineering solution relies on application of generous safety margins and over-designed rotor blades, increasing overall weight and fuel consumption. Intentional aeroelastic design would enable a step-change in technology but is beyond the realms of possibility with existing methods. This is primarily due to a lack of accurate and fast aeroelastic prediction methods and significant gaps in understanding of fluid-structure interactions in complex turbomachinery systems.

Project CONDOR presents a comprehensive research program between Safran Aircraft Engines and Ecole Centrale de Lyon on aeroelastic instabilities in different components of ducted turbomachine architectures with Ultra-High-Bypass-Ratio, including variable pitch fans and high-pressure compressors. The proposed research has significant impact on safety, but also on greenhouse-gas and noise emissions.
Extending a long-established collaboration in form of an Industrial Chair will use synergetic expertise from academy and industry to answer long reaching research questions which are out of scope for small scale projects. Thanks to this collaboration, elaborate and innovative academic methods can be used to advance state-of-the-art technology and enable high-performant and safe propulsion systems for the future.
Within the scientific program novel methods will be developed to investigate multi-physical coupling phenomena between aerodynamics, aeroacoustics and structure vibration. Fundamental understanding of these interactions will require a detailed analysis of complex, three-dimensional and transonic flow, using advanced scale resolving numerical methods (LES). Based on anticipated results of these high-fidelity studies, new pathways for physical modelling and structure interaction will be created. The numerical studies will be complemented by multi-physical experiments with unprecedented and instrumentation. Based on the original studies on different applications, coupling mechanisms will be characterized to enable the development of advanced prediction methods and modelling frameworks which can be employed in an early stage of turbomachinery design.

Industrial Chair CONDOR will provide the necessary framework to establish a solid and long-lasting collaboration between Safran Aircraft Engines and LMFA in the field of aeroelasticity. The expected scientific and technological advances promise a considerable impact for both manufacturers and researchers and will place this partnership among the leaders in aeronautical propulsion.
The character of the collaboration will build the ground for long-term scientific research and the anticipated outcomes are expected to have cross-industrial impact, reaching from aircraft propulsion to sustainable energy production and fundamental science on complex fluid-structure interactions.