Abstract
As an important part of the turbomachinery, the rotor–bearing system has been upgraded to provide a high rotating speed in order to meet the demand of high power production. With increasing demand for stability, the squeeze film damper (SFD) has been widely used in industrial machinery because it can reduce the vibration amplitude and suppress the external force. Usually, it shows inadaptability under the different working conditions where the SFD parameters didn’t change appropriately. Therefore, the reasonable choice of operational parameters of SFD is the key solution that can provide viscous damping effectively and restrain the nonlinear vibration generated by faults. In this paper, the mathematical model of a rotor-ball bearing-SFD system considering the misalignment fault and misalignment-rubbing coupling fault is built first. Then the dynamic characteristics under typical working conditions (ω = 1000 rad/s) of the faulted rotor are discussed. The vibration attenuation effects of the SFD parameters selected by using the multi-objective optimization method on the dynamic responses are analyzed. The results show that when the rotor system operates under different states, the value and the sensitivity of optimization parameters are altered. With no fault, the amplitude of fundamental frequency decrease 23%. With the misalignment fault, the amplitude of the fundamental frequency decreases by 43.4%, the amplitude of 2× fundamental frequency decreases by 27.5%, and the amplitude of 3× fundamental frequency decreases by 66.7%. With the misalignment-rubbing coupling fault, the amplitude of fundamental frequency reduces by 7.4%, the amplitude of 2× fundamental frequency drops by 51.5%, and the amplitude of 3× fundamental frequency drops by 16.8%. Overall, the feasibility of the optimization method of the variable-structured SFD operational parameters for the faulted rotor system is verified. These parametric analyses are very helpful in the development of a high-speed rotor system and provide a theoretical reference for the vibration control and optimal design of rotating machinery.
Highlights
The rotor bearing system of the turbomachinery, such as turbines, pumps and compressors, might undergo nonlinear supported forces and fault excitations
The squeeze film damper (SFD) optimization parameters of the rotor system with no fault are used as the the initial calculated parameters of the SFD of rotor system under misalignment fault, to analyze the initial calculated parameters of the SFD of rotor system under misalignment fault, to analyze the dynamic characteristics of the rotor system with misalignment, in which the misalignment value is e0 dynamic characteristics of the rotor system with misalignment, in which the misalignment value is
Fault the SFD optimization parameters of the rotor system with the fault of misalignment referred in front section are used as the initial calculated parameters of the rotor system SFD, and the x FOR PEER
Summary
The rotor bearing system of the turbomachinery, such as turbines, pumps and compressors, might undergo nonlinear supported forces and fault excitations. With increasing demand for vibration and stability, the squeeze film damper has been widely used in industrial machinery [1]. In 1977, based on Reynolds equation of short bearing assumption, Humes [2] studied the motion law of rigid rotor system with SFD, and the theoretical model of the hydrodynamic oilfilm force was proposed in 1978. The obtained results were in agreement with the experimental results; when Coorper [3] presented the experimental study on SFD, and applied it to the Conway engine successfully, the vibration amplitude of the system was reduced by 60%.
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