Numerical Modelling of Gas Foil Journal Bearings: Analysis of High-Pressure Lubrication Flows

In the pursuit of reducing the climate impact of aviation, there has been an increased interest in the adoption of renewable energy technologies. Examples of revolutionary technologies include hydrogen fuel cell systems and waste heat recovery using the organic Rankine cycle. The design of viable energy conversion systems for aviation poses...

Lubrication theory for Bingham plastics

The rheological behavior of many lubricants used in hydrodynamic bearings can reasonably be modeled using the Bingham plastic material model. This behavior is characterized by a strong discontinuity, from a pure solid state to a viscous fluid state depending on the local shear stress. In literature three methods have been presented to model a...

Modeling and Experimental Validation of a Laval Rotor on Plain Journal- and Turbocharger Floating Ring Bearings - The Behavior of High Speed Rotors on Fluid Film Bearings

The first part of this thesis elaborates on two numerical models of different levels of comprehensiveness of a Laval rotor on plain journal bearings. These models are compared to an experiment, capable of rotating at 60 krpm, also devised in this research. Reasonable correlation in terms of whirl and whip behavior has been found. In the second...

Towards accurate prediction of unbalance response, oil whirl and oil whip of flexible rotors supported by hydrodynamic bearings

Journal bearings are used to support rotors in a wide range of applications. In order to ensure reliable operation, accurate analyses of these rotor-bearing systems are crucial. Coupled analysis of the rotor and the journal bearing is essential in the case that the rotor is flexible. The accuracy of prediction of the model at hand depends on its...