On scaling design and dynamic response prediction of rotor systems

Abstract

Rotor-bearing systems are widely used in wind turbines, gas turbines and other rotating machinery. However, due to economic and realizable factors, it is difficult to directly experiment and test the prototype in the design process of the new rotor system. Therefore, it is very important to design a small-size scaled rotor system that can reflect the dynamic characteristics of the prototype. In this study, a prototype model of the rotor system was established. Based on the similarity theory, six scaled rotor models with different sizes and materials were designed to predict the critical speeds of the prototype rotor system. The results show that when the speed scaling factor is changed, the error of critical speed increases with the decrease of the length scaling factor. The deviation of the first two critical speeds predicted by the model M3, which adjusted the length and speed scaling factor simultaneously, are -0.08% and -0.01%, respectively, this model can accurately predict the first two critical speeds of the prototype rotor system. After the equivalent modeling of rotor system with complex structure, the results presented in this paper can be further applied to the scaling design and fault diagnosis of the full-size rotating machinery.