Study on Mechanism of Lubrication in Porous Journal Bearings. Pressure Distributions in Oil Film under Hydrodynamic Lubrication Conditions.

Abstract

Pressure distributions in the oil film of a porous journal bearing are investigated theoretically and experimentally under hydrodynamic lubrication conditions. The circumferential boundary condition for the oil-film pressure is obtained by applying an integral momentum equation to the oil-film region in the bearing clearance. The oil-film pressure distributions are numerically solved using this momentum equation and taking into consideration the balance between oil fed into the clearance and that lost from it. The present analysis shows the occurrence of a negative film pressure before the trailing end of the oil-film region. The experimental results confirm the existence of this negative film pressure. Furthermore, the angular position of the end of the oil-film region obtained in the present analysis moves toward the downstream region, yielding better agreement of the measured and calculated film regions than those found in our previous analysis using the quasi-Reynolds condition.