Design of High-Speed Coupling for a Micro Gas Turbine Application

Abstract

This master’s thesis, developed in collaboration with MITIS and the University of Liège, presents the design, modeling, and experimental validation of a high-speed flexible coupling for a micro gas turbine intended for biogas-based power generation. The study combines analytical, computational, and experimental approaches to enhance rotordynamic performance and operational stability in compact turbomachinery. The open-source Rotordynamic Open-Source Software (ROSS), coded in Python, was first validated against benchmark models (e.g., the Je cott rotor) and its results showed excellent agreement with numerical simulations from ANSYS and DyRoBeS. Advanced rotordynamic analyses were conducted through Campbell diagrams, modal analysis, and critical speed mapping for di erent configurations of MITIS’s ARBRE 30 and V50 rotors. Structural integrity was verified using Finite Element Method (FEM) simulations in Siemens NX, assessing stress distribution, deformation, and safety margins under rotational speeds exceeding 110,000 rpm and torque loading. An experimental campaign was performed to validate the numerical models. The setup involved a custom-built rotordynamic test bench instrumented with accelerometers, data acquisition systems, and frequency response analysis via Short-Time Fourier Transform (STFT) and Fast Fourier Transform (FFT). Experimental results demonstrated excellent agreement with theoretical predictions, confirming the coupling’s ability to decouple vibration modes between the turbine/compressor and generator shafts. This research establishes a validated workflow integrating Python-based rotordynamic modeling, finite element structural analysis, and experimental vibration testing. The proposed lightweight flexible coupling significantly improves system reliability and enables higher power output for next-generation micro gas turbines. The developed methodology and models form a robust foundation for continued design optimization and industrial implementation within MITIS’s turbogenerator program.