Experimental Validation of the Simulated Steady-State Behavior of Porous Journal Bearings1

Abstract

This study deals with a comparison between new experiments on the frictional behavior of porous journal bearings and its prediction by previous numerical simulations. The tests were carried out on bearings lubricated with polyalphaolefin (PAO)-based oils of distinct viscosities. The theoretical model underlying the simulations includes the effects of cavitation by vaporization and accounts for the sinter flow by virtue of Darcy's law. The effective eccentricity ratio corresponding to the experimentally imposed load is estimated by an accurate numerical interpolation scheme. The comparison focuses on the hydrodynamic branches of the Stribeck curve by dimensional analysis (DA), where the variations of the lubricant viscosity with temperature are of main interest. The numerically calculated values of the coefficient of friction are found to reproduce the experimentally obtained ones satisfactorily well in terms of overall trends; yet, the former lie predominantly below the measured ones, which results in a low-positive correlation between the two.

An experimental and signal analysis workflow for detecting cold-induced noise emissions (cold squealing) from porous journal bearings

“…These "standard bearings" were paired with 8 mm hardened steel shafts, and the experiments were performed on a custommade test rig for precision bearings, named "SLPG2" (from the German "Sinterlagerprüfgerät 2", "porous bearing test device, version 2"), as described in more detail in [15]. Its specific design, see Fig.…”

An experimental and signal analysis workflow for detecting cold-induced noise emissions (cold squealing) from porous journal bearings

“…In an effort to reproduce cold squealing emitted by tribosystems consisting of real porous journal bearings and shafts, we experimented with spherical bearings of 11 mm length and 8.01 mm bore diameter made from sintered steel with 2% copper and a porosity of 20%. These "standard bearings" were paired with 8 mm hardened steel shafts, and the experiments were performed on a custommade test rig for precision bearings, named "SLPG2" (from the German "Sinterlagerprüfgerät 2", "porous bearing test device, version 2"), as described in more detail in [15]. Its specific design, see Fig.…”

Identification of a Material–Lubricant Pairing and Operating Conditions That Lead to the Failure of Porous Journal Bearing Systems

“…Porous journal bearings (PJBs) are impregnated with lubricant to maintain a continuous lubricant supply between shaft and bearing. They operate in the hydrodynamic lubrication regime for most of their lifetime, as long as the pores are still sufficiently filled with lubricant [7]. Under startand-stop conditions (e.g., windscreen wipers [8,9]) or after long and severe operation, the lubricant regime is more likely to be mixed or boundary lubricated, depending on the quantity of lubricant still present in the pores.…”