Dynamic model for high-speed rotors based on their experimental characterization

Abstract

Abstract:Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

Oversampled Modal Approach of a Turbocharger Rotor from the Experimental Lateral Vibrations

“…[38][39][40] In our earlier work, we proposed a simple modal approach to get the natural frequencies with a limited number of degrees of freedom (DOFs) but with considerable estimation errors. 41 Therefore, in this work a theoretical-experimental hybrid method for calculating the natural frequencies and the mode shapes of a turbocharger rotor is proposed. Experimentally it is not easy to get all the bandwidth of a high-speed rotor, however, the mode shapes can be oversampled if the geometry of the rotor allows it.…”