The Optimization of Hydrodynamic Journal Bearings for Aerodynamically Excited Flexible Rotor-Bearing Systems

This paper is concerned with the design of hydrodynamic journal bearings to stabilize a large generic class of turbomachinery subjected to aerodynamic excitation. A modal representation of the rotor is used together with a generalized representation of the bearings. This produces a rather simple set of algebraic equations which may be used to determine optimum bearing designs to maximize the level of aerodynamic excitation for stable operation. This approach has proved useful to quickly select bearing designs which warrant more detailed further investigation. A comparison of results obtained from more elaborate and time consuming analysis methods is made. Also an example bearing optimization is given which illustrates one way in which the present analysis method may be used in the design process.