The Influences of Parameters on the Dynamic Characteristics of a Multi-Foil Aerodynamic Journal Bearing with Bump-Backing Foils: Model Predictions

In this work, the development and implementation of a dynamic characteristics model for a specific multi-foil aerodynamic journal bearing with bump-backing foils (MFJB) is considered. Based on the previously established static characteristics model, the elastohydrodynamic influence is carefully considered, and the perturbation method is adopted, as this model is more effective and computationally efficient. The effects of the operational, structural, and geometric parameters on stiffness and damping coefficients are emphasized. The results show that the eccentricity ratio effects are more intensive when the bearing speed is at a moderately high level, which is no more than approximately 30,000 rpm. The foil thickness has obvious effects on dynamic characteristics, whereas the influence of the elastic modulus is limited. Within the research scope, the eight-foils bearing exhibits a better performance than the four-foils. This paper is designed to provide effective methods and supply theoretical guidance for improving the engineering design and operational stability of bearings.