Dynamic Analysis for the Rotor Drop Process and Its Application to a Vertically Levitated Rotor/Active Magnetic Bearing System

Abstract

Active magnetic bearings (AMBs) have been utilized widely to support high-speed rotors. However, in the case of AMB failure, emergencies, or overload conditions, the auxiliary bearing is chosen as the backup protector to provide mechanical supports and displacement constraints for the rotor. With lack of support, the auxiliary bearing will catch the dropping rotor. Accordingly, high contact forces and corresponding thermal generation due to mechanical rub are applied on the dynamic contact area. Rapid deterioration may be brought about by excessive dynamic and thermal shocks. Therefore, the auxiliary bearing must be sufficiently robust to guarantee the safety of the AMB system. Many approaches have been put forward in the literature to estimate the rotor dynamic motion, nonetheless most of them focus on the horizontal rotor drop and few consider the inclination around the horizontal plane for the vertical rotor. The main purpose of this paper is to predict the rotor dynamic behavior accurately for the vertical rotor drop case. A detailed model for the vertical rotor drop process with consideration of the rotating inclination around x- and y-axes is proposed in this paper. Additionally, rolling and sliding friction are distinguished in the simulation scenario. This model has been applied to estimate the rotor drop process in a helium circulator system equipped with AMBs for the 10 MW high-temperature gas-cooled reactor (HTR-10). The HTR-10 has been designed and researched by the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University. The auxiliary bearing is utilized to support the rotor in the helium circulator. The validity of this model is verified by the results obtained in this paper as well. This paper also provides suggestions for the further improvement of auxiliary bearing design and engineering application.

Eccentric Rotor Drop Dynamics Study of Vertical Maglev Bearing System

“…Figure 4 shows a simplified schematic diagram of the rotor movement under eccentric working conditions. The rotor coupled the rotational and rotational motion states, which were superimposed on each other and acted on the axis locus together [24][25][26]. Most of the axial impact force in the upper angle contact ball bearing group is borne by protective bearing a. Rotor axis displacement, protective bearing an inner ring, shaft between rotors, and radial impact force are the main research parts of this paper.…”

Dynamic Behavior Analysis of Touchdown Process in Active Magnetic Bearing System Based on a Machine Learning Method

“…On the other hand, as discussed in [28,29] and this paper, the major impact forces occur at the first few impacts, this procedure usually takes only about one-tenth of a second, and the variation of the rotational speed of the rotor is neglectable. In this procedure, the motion state of the rotor is mainly affected by the impact forces, and the speeddependent forces, such as centrifugal and gyroscopic forces, play relatively minor roles.…”

“…A detailed description of this system can be found in [11,13,33]. These experiments are performed with various conditions; for example, the brake of drive motor will be applied and an additional axial load (about 2000 N) will be applied by an axial loader [29]. The experiment conditions are summarized in Table 1.…”