Rotor Dynamic Improvement for a Locomotive Turbocharger Available to Purchase

Turbocharger designs typically incorporate fixed-geometry hydrodynamic bearings. These bearings are known to be prone to exhibit sub-synchronous vibration response. This self-induced sub-synchronous vibration component is due to stiffness cross-coupling in the bearings and is independent of the level of rotor unbalance. This type of vibration has been shown to have the potential to destabilize the rotor-bearing system and inducing rapid growth in the vibration amplitude that could lead to mechanical failure. The present work considers the bearing redesign for a locomotive turbocharger with the objective of eliminating sub-synchronous vibration components by increasing the threshold onset speed with no increase in cost or bearing size. The paper describes the characterization of the original design, the optimization of the new bearing design and the experimental validation. As shown in the results, the optimized bearing configuration eliminated the sub-synchronous vibration component within the turbocharger speed range.