Half-Speed Whirl and Load Capacity of Hydrodynamic Gas Journal Bearings

A phenomenological theory of the half-speed whirl of gas bearings is developed; it predicts the existence of four modes of whirl which depend variously on the mass and transverse inertia of the bearing and on the mass and transverse inertia of the shaft. All four modes of whirl have been distinguished experimentally, and related to each other theoretically. From these measurements, it is shown that the half-speed whirl properties of a plain bearing can be considerably improved by cutting an axial slot in the bearing. Further improvement, if required, can be effected by introducing an ovality into the bearing or cutting circumferential grooves in it. The introduction of these anti-whirl devices, however, reduces the load capacity, although measurements have shown the effect is not serious except for the circumferentially grooved bearing