The Theoretical Analysis And Experimental Design On The Performance Of Bump Foil Journal Bearings

Bump foil journal bearing is a new kind of supporting components. The bearing has been widely used in high-speed rotational machinery such as turbo expander etc. The study on the performance of the bearing has a long history. However, there evenly are lots of problems on the theoretical study and practical use of the bearing today, Especially on the building of exact model because it is difficult to take into account the influence of elastic and damping on the performance of bearings.This thesis presents a research on bump foil bearing and the detail is as follows. Firstly, the calculation model of the deflection of bump foil and top foil under uniform press of the air film in the bearing is established by the use of elastic theory. Secondly, the elastic thermal aerodynamic lubrication model is built up, and the program used to solve the model by numerical methods is developed. The distributions of pressure and thickness of the air film are obtained and the temperature distributing of the film is given too. The changes of bearing performance with eccentricity, length-diameter ratio are discussed. At the same time, the comparisons of the pressure and air film thickness distributions between rigid bearings and elastic bearings are shown. Thirdly, the relationship between stiffness and damping characteristics and the parameters such as eccentricity, length-diameter ratio and bearing number is discussed. Finally, several parts and manufacturing die of the bearing are made and experimental test rig is designed for the purpose of examination of the theoretical results.This research laid the foundations for the further theoretical and experiment study on the bump foil bearings. It may have a special reference to the research on the foil bearings and similar bearings too.