Aqueous dispersions of gelled collagen particles. Part 2: numerical technique for tribological properties

The purpose of the paper is to propose a new numerical elastohydrodynamic analysis method suited to cinematic pairs lubricated with aqueous dispersions of collagen gelled media. In comparison with traditional lubricants, these media are characterized by an apparent viscosity that increases with film thickness. Hence the Reynolds equation has been numerically solved taking into account the new rheological law. The proposed analysis method has been applied to a 180 degs partial bearing, which rigid journal rotates in a flexible sleeve, made up by a resin shell. The results of this tribological analysis have been compared with those concerning traditional isoviscous fluids which viscosity has been set equal to the viscosity of the gelled media when the film thickness is constant, i.e. in the unloaded bearing. When the cinematic pair is lubricated with the aqueous gel media, film thickness distribution over the bearing surface is more uniform, active film region is wider and, consequently, peak pressure is lower than when the isoviscous lubricant is employed. This research provides a novel analysis method for studying the tribological behavior of complex fluids with gap-dependent rheology.