Design of a test rig for tilting-pad journal bearings

In the last years, tilting-pad journal bearings are installed with increased frequency in rather a lot of rotating machine applications, typically in high rotating speed cases. The oil-film dynamic coefficients are responsible of the dynamic behaviour and of the stability of the rotor-tilting-pad-bearing system. Therefore the theoretical evaluation and/or the experimental estimation of these coefficients are mandatory for the bearing selection. An experimental test rig for a detailed characterization of standard size five rocker-backed tilting-pad journal bearings has been designed and here described. The bearings could be installed in load-on-pad (LOP) or load-between-pad (LBP) configurations. In particular, Sommerfeld number, steady-state and transient temperatures and pad pressures, dynamic stiffness and damping coefficients in different operating conditions could be evaluated.