<title>Dynamic characterization of a centrifugal compressor rotor by a laser scanning vibrometer</title>

Abstract

The dynamic behavior of a 3D impeller (1100 mm diameter) has been modelled by means of a standard FEM code (ANSYS) and experimentally validated using a laser scanning vibrometer based measurement technique. The theoretical finite element model has been previously developed. Attempts made by using classical measuring techniques has not allowed to obtain the low frequency cyclic modes calculated. Those modes have been obtained using a laser scanning vibrometer. Sine sweep to detect frequencies and sine excitation at resonance frequencies, in order to improve the accuracy of the modal shape, have been used. The keys of success was the ability of the laser vibrometer to detect very low vibration amplitudes (of the order of nanometers) with a high spatial resolution, inside an industrial environment, in very low testing time, all fundamentals for this application. The experimental and numerical activity presented in this work has been carried out from Nuovo Pignone together with the University of Ancona with the final purpose of establishing a new fast procedure to identify, in production industrial environment, the dynamic behavior of large dimensions impellers for centrifugal compressors.