The numerical study of static and dynamic characteristics of multi-layer protuberant foil bearing

Abstract

Multi-layer protuberant foil bearings uses multi-layers of protuberant foils as the elastic support structure to support the smooth top foil. A numerical model with a computational method is developed in this paper to predict the characteristics of the multi-layer protuberant foil bearing. According to this model, the deflection of each foil has been calculated separately with the consideration of the interactions between contacting layers of foils, and the profile of foil deflections, film pressure and film thickness also have been computed. The results show that these profiles of multi-layer protuberant foil bearings are very different from those of bump foil bearings. And the flexibility of the multi-layer protuberant foil bearing is improved as the layer number of protuberant foils increases. Moreover, the effects of the bearing number and the eccentricity on the static and dynamic characteristics of multi-layer protuberant foil bearings have been analyzed. It is found that the bearing always operates with a small attitude angle when the bearing number is large. In addition, the bearing has quite different dynamic characteristics when operating at the critical condition from those at the synchronous condition, which suggests that dynamic computation at the both conditions is required for dynamic analysis of the foil bearing.

Keywords

• gas lubrication
• foil bearing
• load capacity
• protuberant foil
• static characteristics
• dynamic characteristics