Rotor Drop Analyses and Auxiliary Bearing System Optimization for AMB Supported Rotor - Part II: Experiment and Optimization

This paper forms Part II of the rotor drop analysis, focusing on the auxiliary bearing system design and optimization based on the rotor drop analysis methods, as introduced in Part I. Optimization focuses on shaft orbit, maximum ball bearing stress, and how to avoid possible ball bearing damage due to impact loading during rotor drop by optimizing auxiliary design including bearing selection, preload method, radial and axial damping element, and flexible bearing support. The rotor drop modeling process has been validated with test rig result. Using the detailed rotor drop model and time transient method, simulation results are first compared with test data; and a simulation is presented for an 8-stage horizontal centrifugal compressor, are conducted to investigate the effects of auxiliary bearing design and to optimize the auxiliary system. Axial drops, radial drops and combination of radial/axial drops are all evaluated considering angular contact auxiliary bearing size, number of rows, preload, and flexible damped bearing supports in the axial and radial directions. The rotor drop analysis method introduced in this paper may be used as a design toolbox for the auxiliary bearing system.