Abstract
A hybrid gas bearing with water evaporation from ultra-fine porous medium is newly proposed. The proposed bearing is considered to be applied to microturbines and have mainly three advantages suitable for the applications. The first is the stability improved by water evaporation from ultra-fine porous medium. The second is the effective lubrication by liquid water at start and stop of the journal rotation. The third is the cooling effect on the high-temperature journal due to water evaporation. Fundamental characteristics of the proposed bearing are clarified on the basis of a numerical simulation for water vapor, and compared with the conventional bearings the improved performance is demonstrated. Also, transition from water to vapor lubrication is analyzed taking the two-phase properties into account. A preliminary experiment is conducted, and stable start of the journal rotation is confirmed.
