Dynamic behaviour of externally pressurized gas journal bearings with multiple supply holes

A theoretical analysis of the dynamic behaviour of externally pressurized journal bearings using a compressible lubricant is made. Two aspects, (i) “squeeze-film” due to harmonic vibration of a stationary journal and (ii) steady-whirl instability of an unloaded rotating journal were studied. The bearing configuration considered had double plane admission feed holes at quarter station. The effect of recess volume at the downstream of the orifices was considered. The dynamic load and moment were determined for various frequencies, recess volumes and bearing design dimensions. Stability charts of whirl are given for various journal speeds, feed and bearing design parameters.