Characterization of a Rotor Test Rig with Tilting Pad Journal Bearings for High Peripherical Speed

In recent times, the ever-higher peripherical speeds in rotor-dynamics drew the attention of the turbomachinery community. Indeed, the machine rotational speed is crucial for the system efficiency. With this in mind, the design and the assembling of a complete rotor-dynamic test rig were completed at the Mechatronics and Dynamic Modelling Laboratory of the University of Florence. In this setting, the rotor is supported by two tilting pad journal bearings, and it achieves a shaft-bearing surface speed of 115 m/s at 40 000 RPM, thus reaching challenging operative conditions in terms of relative speed between shaft and bearings. Thanks to the proposed test rig, it is possible to study the entire physical phenomena of a rotor-dynamic system, from the dynamic, thermal, and fluid-dynamic points of view. Furthermore, the work validates experimentally the model analysis, in terms of Campbell’s and Waterfall’s diagrams, and rotor orbits. In such a way, working on a real-scale test rig, it is possible to compare models of different types of tilting pad journal bearings under different operating conditions, such as the rotor speed and the bearing lubricant temperature.