The gas bearing test rig was initially developed to determine the feasibility of using a CO2 powered journal bearing design to support the turbomachinery for the 50 kW Zero Emission plant.  The main motivation for using CO2 for to power the bearings was due to the usage of CO2 as the working fluid for the turbomachinery. To ensure no contamination, the same working fluid was chosen for the journal bearings. A static test rig has been built in previous years and is in the process of being upgraded and instrumented. An additional goal for this year was to develop a design modifying the test rig from static to dynamic.

CO2 is fed into separate delivery vessels for each of the journal bearings from a high pressure CO2 tank via Swagelok tubing. From these vessels, the CO2 is supplied to each of the beairngs where it enters the raceway between the bearing and the test shaft through small feed holes. At a given pressure and flow rate, the gas is able to support the shaft. The result is a very low friction bearing, even at high speeds, which would not contaminate the working fluid. The CO2 is then exhausted out out to the recovery pressure vessels and finally to a recovery tank via piping.

Currently, air is being used while the test rig is ensured to be essentially leak free. However, when this is accomplished the test rig will operate as described. The images below show the complete test rig, with a ten dollar bill to show scale.