NEGATIVE PRESSURE IN THE OIL-FILM OF JOURNAL BEARING

In the present paper, negative pressure developed in the oil-film of journal bearing is discussed. Assuming dilatational surface viscosity, negative pressure found experimentally could be reproduced. Parameter study has shown that, when negative pressure is developed: the load capacity increases and the friction coefficient of bearing decreases slightly near the eccentricity 0.6, but this effect reverses at larger eccentricity. Oil flow rate decreases under negative pressure. The locus of center of journal in the bearing clearance is pushed outwards and horizontally under vertical static load. This means that the stability of a turbo-rotor can be reduced, when negative pressure is developed.