Some experiments on oil whirl and oil whip request pdf. Oil whirl is probably the most common cause of subsynchronous instability in hydrodynamic journal bearings. Theory of oil whip for vertical rotors supported by plain journal bearings. Whirl whip induced limitcycle oscillations generated by the outer oil film are more complex and entail a coupled circumferential and radial motion, although the mechanical problem is radially symmetric, if gravity and imbalance are neglected. Oil whirl and whip instabilities within journal bearings. Note that the oil whip frequency never changed even though the machine continued up in speed to 12,000 rpm. The oilwhip instability phenomenon is one of the most important.
Fluid induced instabilities oil whirl and oil whip are characterized as occurring at a subsynchronous vibration frequency. Find whirlpool washer, dryer and kitchen appliance manuals you can download from our website. Dryfriction whip and whirl predictions for a rotorstator. Oil whirl and oil whip 6 are the most common rotordynamics phenomena occurring in turbocharger semifloating ring bearing systems. Request pdf dryfriction whip and whirl predictions for a rotorstator model with rubbing contact at two locations the present work investigates the phenomena of whip and whirl for a. In an earlier paper 1 the oil whirl of a rigid rotor was considered.
The second type whip was also a selfexited vibration. These interactions will make the rotor impact the wall of the journal bearing. During whirl, the rotor system precesses at a natural frequency that is controlled by the softer bearing spring stiffness. In this study, we investigate the onset of instability on a flexible rotor mounted on two plain cylindrical journal bearings. Significantly large magnitudes of subsynchronous motion occur during oil whirl and oil whip. Eeing of positive type, if cannot slip under heavy pressure and slow speed. Oil whirl, oil whip and whirlwhip synchronization occurring in rotor systems with fullfloating ring bearings article in nonlinear dynamics 574. Whirl and whip rotorbearing stability problems agnes muszynska bently rotor dynamics research corporation mi nden, nevada 89423 a mathematical model of a symmetric rotor supported by one rigid and one fluid lub ricated bearing is proposed in this paper. Active elimination of oil whip and dry whip through the use of electromagnetic exciter conference paper january 2010 with 37 reads how we measure reads. The oil whirl was suddenly replaced by oil whip a lateral forward precessional subharmonic vibration of the rotor. Differentiating between fluid induced instability oil whirl and oil. Downloading manuals is also a convenient way of obtaining a backup in case your original document goes missing. Typically, the oil film itself flows around the journal. Whirl a whip 309 s 3rd st, girard, illinois 62640 rated 4.
Oilwhip is a severe vibration which occurs when the oilwhirl frequency coincides with the first flexural natural frequency of the shaft. The whirl vibration is usually associated with a rigid body mode of the rotor system figure 2, top. Results of the eigenvalue analysis of the linearized rotorbearing system. However, there is a lot of confusion on the parameters that affect the onset of instability. Oil whirl of a rigid rotor in 360 journal bearings. A nice way to put it is someone who keeps people in check, but a whip wielder is essentially someone who bosses other people around. The fluidinduced instability behaviors are oil whirl and oil whip. In general, the harmonic order of oilwhirl subsynchronous vibrations is close to 0. Offshore oil services incorporated all rights reserved radio call sign maximum beam midship depth gross tonnage net tonnage summer freeboard summer draft. Whirling definition, to turn around, spin, or rotate rapidly. The oil whirl and oil whip phenomena are well known since the early twentieth century.
The onset of whirl is predicted at 2400 rpm followed by a gradual transition to whip above 3000 rpm. Conveyin ideas through improvisational music, poetry, photography, and other arts. At this point, the oil whip frequency remains the same, independent of the rotor rpm. On the instability threshold of journal bearing supported rotors. Frequency enhancement of oil whip and oil whirl in a. Whip is an instability vibration that locks to a more or less constant frequency. Nuwhirl hercules hydromassage bath pump us parts center. Towards accurate prediction of unbalance response, oil. Whirlpool manuals can help you get the most out of your appliance, and provide important information about parts and accessories. Effects of the hot alignment of a power unit on oilwhip instability. Thus, whirl whip instability in the outer fluid film may be interpreted as symmetry breaking.