The ARMD software package is capable of facilitating comprehensive evaluations of fluid-film bearings. In such light rotors, it is also possible that the oil-whirl component becomes very small or vanishes during the rotor crossover through the critical speed, giving place to the rise of the synchronous component due to unbalance 11 For horizontal rotors with higher eccentricity ratio, the subsynchronous oil-whirl component may be present in the bearings but usually with small amplitudes.
8, the channels 45 in the thrust face 44 of the thrust plate 42 consist of four (4) circumferential channels or rings 50, 51, 52, & 53 interconnected by a plurality of generally radially extending arcuate channels 56. The feeder holes 43 journal & thrust combined bearing provide bleed air from the radially extending orifices 41 to the arcuate channels 56. Each arcuate channel 56 may be supplied by a single feeder hole 43 or there may be a plurality of feeder holes for each arcuate channel 56. In FIG.
The seat 18 is a radial recess provided on the inner surface 13 of the bearing housing 11 and has the shape of a parallelepiped having an opening on the inner surface 13, a plane base opposite to the opening and four plane lateral surfaces connecting the plane base to the opening.
It is another object of the present invention to take advantage of the fact that the compressor discharge gauge pressure varies with the square of turbomachine speed to assure that the hydrostatically generated thrust forces are also proportional to the square of turbomachine speed.
However, to provide adequate bearing compliances for overall load capacity and damping of disturbances to the runner, the spring is required to possess a lower spring rate, yet such a lower spring rate militates against maintenance of proper wedge shape and risks contact between the runner and foils under operating conditions, thereby risking damage to those members and failure of the bearing.
In view of this the bearing is designed so that when the two halves of the housing are correctly bolted together its parting line surfaces adjoin and the bearing correctly conforms to the housing, leaving the required running clearance between its working surface and the journal.
For good operation of the bearing, it is imperative that the fluid film between the sheets and the shaft never be destroyed, in particular by unbalance of the bearing, by the weight of the shaft, by vibrations, by acceleration and by the gyroscopic effects resulting from the rotation of the shaft or of the casing and the displacement of the bearing, for example rising in an aircraft.