EXPERIMENTAL INVESTIGATION OF FIXED-GEOMETRY THRUST BEARING TAPER GEOMETRY ON CRITICAL OPERATING PARAMETERS

This research presents a newly developed hydrodynamic test rig for experimental testing of hydrodynamic thrust bearings. In this study, the test rig applies thrust loads up to 500 lbf at rotational speeds up to 6,000 rpm. Three fixed geometry hydrodynamic thrust bearings with eight identical helically tapered thrust pads made of cast aluminum alloy have each been machined such that the depth of their tapered surface at the leading edge is 0.0005”, 0.0015”, and 0.0025” with all other geometrical features held constant. The test rig includes an oil conditioning system which supplies a constant flow of ISO 32 motor oil to the test bearing at 40°C. An integrated sensor system includes an eddy current sensor to measure the minimum oil film thickness, a friction torque moment arm with load cell to measure power loss, K-type thermocouples to measure bearing temperature, pressure transducers to measure oil film pressure distribution, and load cells to measure the applied thrust force. The test rig also introduces a novel bearing alignment system used to ensure precise alignment of the bearing and runner during operation based on pressure feedback from individual thrust pads. Results obtained from this experiment are used to compare the effect of taper geometry on active performance of the test bearings considered. Trends in performance observed are related to the trends predicted analytically by the Reynolds equation.