Study of the lateral vibration in a multistage rotor

This paper presents the development of theoretical and experimental models for the study of rotodynamic behavior of a multistage rotor. The transfer matrix method, which includes the characteristics of stiffness and damping for the supports and the stages respectively as well as the characteristics of unbalance in the stages, is used for the theoretical model. The data from a physical model was employed as a way of validating the theoretical results. The first two critical speeds were determined with the theoretical model and they differ in a low percentage with respect to the values measured experimentally. Moreover, the vibration level recorded in the physical model rises 2.5 times when the multistage rotor approaches the first two critical speeds. In addition to this, significant displacements of the lateral critical speeds are noticeable when an increase in mass imbalance is induced in several of the rotor impellers.