Implementation of a Forced Response Aero-Engine Experiment for Characterization of Fan Flutter Damping
Name
bron-joabron-sm-aeroastro-2026-thesis.pdf
Size
18.91 MB
Format
Adobe PDF
Checksum (MD5)
8c638da7bc0f8581621eaeb0ded08219
Author(s)
Bron, Joachim A.
Advisor(s)
Spakovszky, Zoltán S.
Date Issued
May 2026
Publisher
Massachusetts Institute of Technology
Abstract
Flutter in aero-engines continues to pose a problem, with several fatigue-related fan failures recorded in recent years. Despite the use of modern tools, computing fan flutter stability boundaries still remains a challenge. This thesis presents the design and implementation of an experiment for forced-response characterization of fan flutter damping in a full-scale aero-engine. The improved characterization of engineering safety margins has the potential to reduce time and costs in engine testing and certification.
An actuator array to excite different fan flutter modes was designed and demonstrated that the spatial excitations meet design intent within 4%. The zero-net mass flux actuators, used to provide the flow perturbations, were found to suffer from a 60% decrease in authority when installed in the actuator array environment due to the closely coupled perforated screen and back-cavity. Despite this loss in authority, virtual experiments demonstrate the forced response experiment to be feasible in the presence of noise, with less than 5% mean error in inferred flutter damping for the relevant modes at part- and at takeoff speed conditions.
The actuator setup was assembled, commissioned and mounted on the engine inlet. The fan casing was modified to accommodate vibration sensors. Vibration measurement locations were informed by blade tip mode shapes. Safe vibration limits were determined for future experiments to ensure blade stresses do not exceed 20% of the Goodman fatigue limit.
This thesis also demonstrates that pressure sensor based vibration measurement offers an opportunity for characterizing blade vibrations at reduced cost relative to traditional blade tip-timing sensors. Preliminary assessment of unsteady an casing pressure signals suggests viability for vibration measurement.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Terms of Use
In Copyright - Educational Use Permitted
Copyright retained by author(s)
Persistent DSpace Link
