A HIGH SPEED TEST RIG CAPABLE OF RUNNING AT 190,000RPM TO CHARACTERIZE GAS FOIL THRUST BEARINGS

This paper details the design and performance of a highspeed (up to 190,000rpm) gas foil thrust bearing (GFTB) test rig to measure bearing load capacity. Several GFTB test rigs were reported in the literature for operating speed up to 90krpm. A few recently presented works show successful runs at 135krpm for testing gas thrust bearing with viscoelastic support and 130krpm tilting pad thrust bearing with compliant structure. However, a GFTB test rig for speed range over 100krpm has not been reported. At high speed operation, the gas film thickness of the GFTB is around a few microns which makes it difficult to achieve in testing. In many cases, the measured thrust load from experiments is well below the predicted data due to difficulty in testing and instrumentation. Difficulty in validating the actual load capacity of the bearings leads to increasing the thrust bearing size to ensure sufficient load capacity in actual applications, which results in higher power consumption. This work presents detail feature of a novel GFTB test rig and test results of 38mm GFTB. The developed test rig runs up to 190krpm and measures bearing load capacity, frictional torque and temperature across bearing ID and OD. The test rig is suitable for testing GFTB with OD from 30 mm to 40 mm. The test facility successfully tests a 38 mm GFTB to its predicted load capacity of 75N (110kPa).