Computational Analysis of Foil Air Journal Bearings Using a Runtime-Efficient Segmented Foil Model

Abstract

This contribution is concerned with the development and the implementation of a foil air journal bearing model. For this purpose, the numerical procedure solving the Reynolds equation for compressible fluids has to be coupled to a compliant foil model. The presented beam-based approach is supposed to reproduce most of the experimentally known particularities in the mechanical behavior of the foil structure, while being at least as runtime-efficient as the commonly used simple elastic foundation model. The developed modeling approach will be validated by comparing simulation results to data found with a more complex reference model. In the analysis part, most notably, the top foil compliance is shown to deteriorate the load-carrying capacity of air bearings. Moreover, the influence of the top foil compliance on the dynamics of a rigid rotor supported by two foil air journal bearings will be discussed.