Abstract
The effects of pressure difference between both ends of journal bearings, mean radial clearance and bearing length on the stability threshold speed are investigated experimentally. A testing apparatus to measure the stability threshold speed is constructed. A symmetric horizontal flexible rotor is supported by a rolling bearing at one end and by a test bearing block at the other. The test bearing block is composed of two identical cylindrical journal bearings with a full circumferential groove between them, and oil is supplied into the groove at high pressures. It is found that experimental results are in good agreement with the theoretical results described in the preceeding reports. It is also found that the theoretical analysis taking into account the pressure drops mainly due to the axial acceleration of the oil at the inlet end of the journal bearing is confirmed to be applicable to the stability analysis of a flexible rotor supported by journal bearings with pressure differences.
