Experimental investigation on the dynamic properties of tilting pad journal bearing

The hydrostatic and hydrodynamic performance of a tilting pad journal bearing was experimentally investigated in terms of the variation of load, rotating speed and exciting force frequency by an on-line computerized testing and analyzing method. The bearing is a LBP four-pad tilting pad journal bearing with the diameter of 152.15 mm and a length to diameter ratio of 0.703. The clearance ratio of the bearing is 0.0021, and the static load applied on the bearing is 10 kN, 20 kN, 30 kN and 40 kN respectively. The maximum rotation speed of the bearing is 6000 r/min, and the ratio of the excitation frequency to the frequency of the rotating shaft ranges from 0.43 to 2.0. The magnitude of the excitation force is controlled to make sure that the bearing has a linear behavior in operation. It is found that under different frequencies of dynamic exciting force, the theoretically calculated coefficients of the bearing are quite different from the experimental results. It is also found that the variation of the excitation frequency in the experiment has a less effect on both stiffness and damping coefficients than that predicted by the theoretical method.