Stability of externally-pressurized air-lubricated porous journal bearing is studied experimentally and theoretically. The effects of varing supply pressure and clearance on stability are experimentally investigated for the unloaded porous journal bearing with the rotor rotating vertically. Theoretically computed critical mass for the experiment is compared with the experimental results.
In this work it is shown that increase in supply pressure makes the whirl instability threshold speed increase and clearance change has a little influence on the whirl instability threshold speed. And the resonance speed of rotor-bearing system increases with increasing supply pressure.
There is some difference between critical mass obtained from the experimental result and critical mass obtained from theoretical computation for the experimental conditions. But experiment and theory show the same tendency to increase critical mass when supply pressure is increased.
