EXperimental study on mechanism of lubrication in porous journal bearings. (1st report. Oil flow in porous media).

Abstract

The oil flow in the porous media is experimentally investigated to explicate the mechanism of lubrication in the porous journal bearings. For the test bearing, a simplified model of the porous bearing is used, whose matrices are composed of the packed glass spheres having small uniform diameter. To visualize the flow in the porous media, a dyed oil is fed into the porous media impregnated with uncolored oil and the fluorescent flow is rendered visible by the ultraviolet flash lamp. It is found that there exists the circulation of the Oil flow through the porous media, which the flow contributes to the lubrication in the porous bearings. In hydrodynamic lubrication conditions, the oil in the porous media flows away from the position of the load line towards the unloaded region. However, in boundary lubrication conditions, when the oil supply pressure is relatively small, the oil in the porous media flows from the loaded region towards the site where the oil film pressure would be negative.