Session: 32-08 Fan & Propulsor Design

Paper Number: 103629

103629 - Experiments on Tuned Uhbr Open-Test-Case Fan Ecl5/catana: Performance and Aerodynamics 

Latest design trends in turbomachinery, especially concerning the geared turbofan, result in fan geometries with lightweight, 3D-shaped rotor blades with reduced tip Mach number. Existing design criteria are not suitable to capture coupled aerodynamic, structural and acoustic phenomena emerging in these modern architectures. The combination of advanced numerical methods and experiments at representative conditions is required to enhance the understanding of complex multi-physical interactions and thus allows to improve design concepts. Existing reference configurations like the NASA rotors 37, 67 or the TU Darmstadt Rotor 1 are high—speed designs and not representative for modern Ultra-High-Bypass-Ratio (UHBR) fans. To overcome this gap of available configurations, the open-test-case composite fan ECL5 has been developed at Ecole Centrale de Lyon. Detailed geometry and structural properties have been shared with the research community [Pages et al.: UHBR Open-Test-Case Fan ECL5/CATANA. https://doi.org/10.3390/ijtpp7020017] and are already used by over ten international research institutes. In project CATANA (catana.ec-lyon.fr) numerical and experimental studies are conducted and in the proposed paper, the first experimental results will be published.

The design process of the stage was based on industrial goals like high efficiency and low blade count and weight, resulting in a 16-bladed composite fan with a tip Mach number of 1.02 at design speed. The fan stage is experimentally investigated on the facility ECL-B3, which provides extensive synchronized steady and unsteady instrumentation for aerodynamics, acoustics and structure dynamics, enabling the analysis of complex coupled phenomena.  

In this study, the tuned rotor configuration is investigated at different speedlines and operating conditions, ranging from choke to near-stall. The results focus on performance of the machine, in comparison with original design objectives and previously published numerical simulations. Global performance and local aerodynamic features are discussed in comparison between experiments and simulations, highlighting prediction challenges and requirements for advanced numerical methods.

The paper will additionally provide detailed information about probe positions, measured tip clearance and blade stagger angle as a function of rotational speed and operating condition for all blades. Further properties such as individual blade mass, center of gravity etc. are provided to enable further analysis on real test parameters. Particular focus is laid on the evolution of circumferential asymmetry arising at loaded conditions due to blade untwist, which has been identified as a characteristic issue for low-transonic composite fans, for the first time investigated using multi-physical and synchronized instrumentation.

The presented study provides an extensive experimental dataset to validate numerical investigations on multiple levels of fidelity and serves as a reference for future experiments on a structurally mistuned configuration.

Presenting Author: Alexandra P. Schneider Ecole Centrale de Lyon

Presenting Author Biography: 2020: Master of Science in Mechanical and Process Engineering at Technische Universität Darmstadt (TUDa)
since 2020: PhD student at Ecole Centrale de Lyon

Authors:

Alexandra P. Schneider Ecole Centrale de Lyon
Anne-Lise Fiquet Ecole Centrale de Lyon
Benoit Paoletti Ecole Centrale de Lyon
Xavier Ottavy Ecole Centrale de Lyon
Christoph Brandstetter Ecole Centrale de Lyon