Pneumatic hammer instability in the aerostatic journal bearing–rotor system: A theoretical and experimental analyses

Abstract

In this study, the pneumatic hammer instability phenomena in the aerostatic journal bearing–rotor system is analysed and discussed for different feeding hole configurations theoretically and experimentally. The influences of the configuration of the feeding holes on the nonlinear dynamics of the system are also investigated. The air flow between the surfaces is modelled with Reynold’s equation and it is numerically solved with differential transform and finite difference hybrid method. Three different aerostatic bearings are modelled and simulated to investigate the ınfluences of the configuration of the holes for different angular speeds. An experimental test rig is designed and tested for different rotor speeds to validate the obtained numerical results. The dynamic response of the system is analysed using waterfall plots, bifurcation diagrams, orbit plots, phase portrait and Poincaré map, which are drawn to determine the pneumatic hammer instability region of the modelled system. The results reveal a nonlinear dynamic response of the rotor centre. In addition, the analysis shows that the feeding hole configuration affects the rotor dynamics and the pneumatic hammer instability region.

Design and optimization of fluid lubricated bearings operated with extreme working performances—a comprehensive review

“…Pneumatic hammer vibration is a self-excited and selfsustained vibration that commonly occurs in practical engineering scenarios [30]. The large vibration amplitude is accompanied by continuous whirling, which usually causes lubrication failure and can damage high-end equipment.…”

Investigation of different parameters on nonlinear dynamic behaviors of vertical rotor system supported by aerostatic bearings

“…Dal [20] analyzed the pneumatic hammer instability phenomena in the aerostatic journal bearing-rotor system and found that the different feeding hole configuration affects the rotor dynamics and the pneumatic hammer instability region.…”