Design and analysis of a slotted bump foil bearing with a grooved sleeve for enhanced load capacity and stability

Abstract

This paper proposed a novel slotted bump foil bearing with a grooved sleeve to enhance ultimate load capacity and stability. The structural stiffness is designed in stages along both the circumferential and axial directions to better coordinate foil deflection with film pressure. An aero-elastic coupling algorithm is developed that incorporates the three-dimensional distribution of the support structure and normal contact forces. By treating these forces as distributed loads, the model accounts for stiffness variations and provides a realistic depiction of the contact state. The accuracy of the algorithm is validated through experimental results and subsequently applied to evaluate the bearing performance. The results reveal that the grooved sleeve expands the high-pressure zone within the air film. Meanwhile, the slotted bump foil reduces stiffness at the edge-plane, leading to a more uniform axial film thickness and improved anti-overturning capability. Compared with first-generation foil bearings, the proposed design achieves a 31.24% improvement in ultimate load capacity at 3.2 µm minimum film thickness. The settling time is also significantly less than that of other bearings.