Active Lubrication for Eliminating Instability Problems in Rotating Machines

When the hydrostatic and the hydrodynamic lubrication are simultaneously combined in a journal bearing, with the aim of reducing wear between rotating and stationary parts, one refers to the hybrid lubrication, which offers the advantages of both lubrication mechanisms. When part of the hydrostatic pressure is also dynamically modified by means of hydraulic control systems, one refers to the active lubrication. By the combination of fluid power, electronics and control theory, the active lubrication makes feasible the reduction of wear and the attenuation of rotor instabilities. Significant reduction of resonance peaks is demonstrated in a test rig, specially designed with the aim of experimentally exploring the potential of the active lubrication. Experiments are led in the frequency domain.