Vibration response analysis of gas generator rotor system with squeeze film damper based on dynamic similarity

Abstract

For the aero-engine rotor system with complex vibration responses, a simplified model based dynamic similarity is proposed to study the vibration characteristics of that. On the basis of the principle of dynamic similarity, a simplified model of the combustion-driven rotor is obtained, with the criteria of the same critical speed of each order and similar vibration modes, while keeping the layout of the structure unchanged. By comparing the vibration characteristics of the actual rotor with those of the simplified model through theoretical analysis, there is less than 2.59 % error between the simplified model and the actual rotor. The rationality of the research method, which is developing the simplified model based on dynamic similarity to study the vibration response law of the original rotor, is demonstrated. Then, the unbalance response law of the rotor with a squeeze film damper is explored expanding on the produced model, and the study shows that the unbalanced excitation can significantly reduce the response. Finally, the influence law of the phase of unbalance excitation is experimentally verified on the test rotor. The results show that the simplified model of the actual rotor based on dynamic similarity can well reflect the vibration characteristics of the original rotor, and the proposed analysis method has an important reference role in studying the vibration mechanism of the aero-engine rotor system.