Identification Dynamic Force Coefficients of a Five-Pad Tilting-Pad Journal Bearing

The investigation of steady state and dynamic effects is essential in the field of rotor dynamics to evaluate the behavior of hydrodynamic bearings. This paper describes an experimental study which was conducted on a test rig to determine dynamic performance characteristics of a tilting-pad journal bearing (TPJB). The tests have been carried out on five-pad TPJBs with a nominal diameter of 100 mm, a length-to-diameter L/D of 0.7 and load-on-pad (LOP) and load-between-pad (LBP) configuration. The stiffness and damping coefficients are evaluated from multiple frequency excitations (25–50 Hz) exerted on the bearing housing by a pair of hydraulic actuators, varying load direction and unit load using experimental data considering the linearized expression of the oil-film forces. The results show that the dynamic damping force coefficients are not strong functions of the frequency of excitation, unit load or load direction. However direct stiffness coefficients seem to be affected by frequency of excitation, unit load or load direction, in which unit load has a strong effect on direct stiffness coefficients.