Experimental Determination of Load-Carrying Capacity of Modified Tapered-Land Hydrodynamic Thrust Pad Bearings

Abstract

Abstract In this study, a method for increasing specific load on hydrodynamic thrust bearings is introduced and experimentally evaluated. Experimental determination of thrust bearing load capacity is limited by the applied load capability of test equipment which may be unequipped to create specific load magnitudes for application-sized bearings. Theoretical analysis of Reynolds equation suggests there is a linear relationship between the number of pads on a thrust pad bearing and the maximum thrust load a bearing can support. Two bearing samples, one with 8 active thrust pads and the other with 4 similarly sized active thrust pads are fabricated and subjected to an experimental test matrix. Each bearing is tested at 20 different combinations of steady-state speed and thrust load all at consistent oil inlet conditions. Sensors integrated in the test rig measure the magnitude of hydrodynamic pressure acting on the middle of the thrust pads along with bearing temperature and minimum oil film thickness. Results from this study show that reduction of the active thrust bearing surface area by half was shown to increase the hydrodynamic pressure acting on the bearing by nearly 100%. Removing active thrust pads is proven to effectively multiply the specific load on the bearing pad and create a more extreme operating condition under lower thrust force without increasing the bearing size envelope and/or undergoing time consuming and costly test rig upgrades.