Bearings for turbomachinery

Due to the today’s increasing demand of higher efficiency for all machines, new lubricated bearings are facing extreme operating conditions and their behaviour must be investigated. The bearing stiffness and damping coefficients must be known for rotor dynamic analyses particularly at the design stage. The coefficients are experimentally identified with linear models by applying dynamic loads to the bearing, measuring the rotor-stator relative displacement.

A test bench (Fig.1) has been designed and realised for testing large size bearings operating at high peripheral speeds and static loads. Particularly tilting pad journal bearings and roller bearings can be tested with the test rig. Both static and dynamic characteristics of the bearings can be investigated.

As an example, a picture of a 4-pads ball-in-socket tilting pad journal bearing with 280mm diameter is shown in Fig.2.

Fig. 1 – Photograph of the test rig.
Fig. 2 – Four pad journal bearing.

Research group
Enrico Ciulli, Paola Forte

External collaborations:
Baker Hughes
Nuovo Pignone Tecnologie


Funding:

POR CReO FESR 2007-2013 Linee di Attività 1.5.a e 1.6. (Bando Unico R&S anno 2012) – Progetto: “Advanced Technologies for Energy Efficiency (ATENE)”

Main publications:

  • E. Ciulli, P. Forte, M. Libraschi, M. Nuti, “Set-up of a novel test plant for high power turbomachinery tilting pad journal bearings“, Tribology International 127 (2018) 276–287. DOI https://doi.org/10.1016/j.triboint.2018.06.014
  • E. Ciulli, P. Forte, “Nonlinear Response of Tilting Pad Journal Bearings to Harmonic Excitation”, Machines 2019, 7(2), 43; 14pp. doi:10.3390/machines7020043
  • G. Vannini, F. Cangioli, E. Ciulli, M. Nuti, P. Forte, J. Kim, R. Livermore-Hardy. “Experiments on a Large Flexure Pivot Journal Bearing: Summary of Test Results and Comparison with Predictions“, GT2019-90278, Proceedings of ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT2019, June 17-21, 2019, Phoenix, Arizona, USA, 1-9.
  • M Barsanti, E Ciulli and P Forte, “Random error propagation and uncertainty analysis in the dynamic characterization of Tilting Pad Journal Bearings“, RASD 2019, IOP Conf. Series: Journal of Physics: Conf. Series 1264 (2019) 012035. doi:10.1088/1742-6596/1264/1/012035