Proorly lubricated fludi film bearing: 0.33 x whirl phenomenon

摘要

In a gas turbine-generator set, equipped with a floating ring bearing, an unusual whirl frequency (0.33x) has been observed. To clarify that, vibrational data was taken from a laboratory rotor rig. Poor lubrication at the flud-film bearing cause the appearance of specific subsynchronous vibrations in the rotor vibrational response. Lubricant starvation in the fluid-film bearig resulted in decreasing of the flud circumferential flow. When the rotor was in 0.47x fluid whirl conditions, the journal acted like a pump, pump, pumping the oil out of the bearing, not only through the usual drain openings, but even through the spupply pipes, and, therefore, gradually accelerating lubricant strarvation. This occurred at a low supply pressure pressure of the lubircant at high rotational speeds. The reverse flow of oil and air bubbles was observed in plastic, transparent supply pipes.