The Challenges of Oil Free Bearings in Micro-turbomachinery

Among all types of bearings, gas bearings are the most environmental friendly supports as they do not need to be lubricated with mineral oil. The air or the gaseous working fluid used in micro-turbomachinery are used to lubricate the bearings and realize the supporting task. Due to their characteristics, they cannot replace the other bearings in all applications; however, the research is always working in order to broaden the boundaries of gas bearings. This paper is aimed at describing the most promising application domains in which gas bearings are challenging and gives a survey on all types of gas bearings, discussing their pros and cons.