Proof-of-Concept Experimental Validation of a New Active Hydrodynamic Bearing

Flow-induced instabilities known as ‘whirl’ and ‘whip’ are the main contributors to self-excited vibrations in fluid-film bearings. In this paper, we experimentally evaluate a new active hydrodynamic bearing designed to lessen flow-induced vibrations in rotating machines. The active system consists of a fluid-film bearing with a motor-actuated rotating bushing that serves as the control input. This input is used to adjust the mean flow velocity in the bearing and indirectly control the whirl vibration. A PID-type control law is used to adjust the bushing speed. An experimental test rig that realizes the active bearing concept is introduced. Experimental results are presented comparing the active bearing with PID-type control and open-loop control to the passive bearing operation. The results show that the active bearing with feedback control is effective in eliminating whirl vibrations.