Formulation of a Transfer Function between rotor responses on a High Speed Balancing Machine and in Turbo Machinery by System Identification

In this paper the authors propose an innovative method for the determination of a transfer function (MTF) between the rotor responses on a balancing machine (HSB) and on turbo machinery (SP). The prediction of the rotor behavior in its turbomachine final housing is a crucial problem for turbo machinery manufacturers and very complex to solve using classical approaches. The proposed method uses a particular MTF formula, calculated with a black/box approach based on the application of the theory of System Identification, using the rotor responses in SP and in HSB as input and output respectively. MTF was determined by a regression analysis of the responses in HSB and SP of 10 rotors; subsequently it was tested and validated on other 15 rotors. The results demonstrate that proposed MTF simulates a rotor behavior in SP with a satisfactory overlapping of the measured output.