Hybrid gas bearing effectively stabilized by water evaporation from ultra-fine porous medium

Abstract

A hybrid bearing effectively stabilized by water evaporation from ultra-fine porous medium is proposed and its basic characteristics are clarified by numerical simulation and experiment. The proposed bearing aims to be applied to MGT (Micro Gas Turbine) and has mainly three advantages suitable for application to MGT. The first is the stability improved by water evaporation from ultrafine porous medium. The second is the effective lubrication by liquid water at the start and stop of the journal rotation. The third is the cooling effect on the high-temperature journal due to water evaporation. A fundamental experiment from water lubrication to vapor lubrication via transition state has been carried out. The experiment indicated the potential of vapor lubrication and confirmed the stable start-up at water lubrication.