Cavitation effects and heat transfer of saturated water-lubricated journal bearings for a turbo machine.

The loss, stability, and heat transfer of water lubricated bearings of a turbo machine, and the effects of cavitation were studied. When the sub-cool of lubricant water is small, vaporous cavitation is likely to appear. Vaporous cavitation is essentially different from gaseous cavitation of general oil-lubricated bearings in that the evaporation of lubricant occurs which involves latent heat. Because the vaporous cavitation reduces the viscosity loss, and the bearing is cooled not only by sensible heat but also by latent heat, the bearing temperature elevation is suppressed. Another effect of cavitation is stabilization of half speed whirl. We conducted a water-lubricated bearing experiment which consists of 2 conical journal bearings, to confirm the above effects quantitatively.