Determination of the Inertia of a High-Speed Low-Pressure Turbine Rotor Assembly

This master's degree thesis is the project's report of the internship completed by the candidate at the Von Karman Institute for Fluid Dynamics in Rhode-Saint-Genèse, Belgium, between May 2024 and November 2024. During the internship a prototype of a high-speed, low-pressure turbine stage for a geared turbofan engine was mounted on the CT3 facility; this stage, designed by Safran Aircraft Engines, had previously been tested on the same facility of the Von Karman Institute (VKI) within the Clean Sky 2 project SPLEEN. The primary objective of this project is to accurately determine the rotor's actual inertia to validate the results of the SPLEEN project, aiming for a result that closely matches the value obtained from the CAD model, as well as aiming to a target uncertainty on all measurements around or less than 0.5%. Achieving such precision is critical, as the inertia value plays a key role in assessing the turbine stage's efficiency: an error of 1% on the inertia evaluation propagates as an error of 1% in the efficiency value. The candidate has to develop a stable experimental setup for the encoder connection to the rotor disk as well as the rotor-mass connection: this is obtained by connecting a mass falling from the ceiling to a steel wire connected to the rotor. In parallel of the experimental setup design, selection, purchasing and manufacturing of all of the necessary components, the candidate has to create a coding routine in order to post-process the experimental data gathered from the tests. The candidate has to run several tests with slightly different setups (for example the mass can be increased, or a different angular velocity range can be selected during the post processing routine) to obtain an accurate estimation of the inertia of the rotor and its uncertainty.