Hydrodynamic self-lubricating journal bearings analysis using Rabinowitsch fluid lubricant. (December 2019)

• Record Type: Journal Article
• Authors: Boubendir, S.; Larbi, S.; Malki, M.; Bennacer, R.
• Is Part Of: Tribology international. Volume 140(2019)
• Publication Date: 2019-12
• Subjects: Non-Newtonian fluid -- Rabinowitsch fluid model -- Porous journal bearing -- Hydrodynamic lubrication; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2019.105856
• Languages: English
• ISSNs: 0301-679X

Abstract

Abstract: In this study, the effects of non-Newtonian pseudo-plastic lubricants behavior, using Rabinowitsch fluid model, on static characteristics of circular self-lubricating porous journal bearings of finite length with sealed ends are highlighted. The nonlinear Reynolds equation based on the Rabinowitsch fluid model has been developed specifically for porous journal bearing cases by considering the fluid flow in the porous matrix described by Darcy's law. The Governing equations are discretized using a centered finite difference scheme and solved numerically using an iterative method. Following to the absence of the porous matrix or the non-Newtonian fluid behavior, the obtained results showed a good agreement with those of the literature review. The static characteristics of hydrodynamic lubrication are calculated numerically for various parameters such as bearing dimensions; the porous bush permeability and the lubricant pseudo-plastic coefficient. It is shown that the dimensionless permeability has significant effects on the static characteristics of the bearings. The pseudo-plastic lubricant coefficient decreases the bearing characteristics (load capacity, pressure) compared to Newtonian lubricant cases. The use of the pseudo-plastic fluids reduces the performance of the bearings and this reduction grows with the porous bearing properties. Highlights: The effects of non-Newtonian pseudo-plastic lubricants, using Rabinowitsch fluid model, on static characteristics of circular self-lubricating bearings are highlighted. Reynolds equation based upon the Rabinowitsch fluid model has been developed specifically for porous journal bearing cases. Static characteristics of hydrodynamic lubrication have been calculated numerically for various parameters (bearing dimensions, porous bush permeability and lubricant pseudo-plastic coefficient). It is shown that the dimensionless permeability has significant effects on the static characteristics: when the permeability increases, the pressure and load capacity decrease while the friction coefficient increases especially at higher eccentricity ratios. In comparison with the Newtonian fluid case, the pressure and load capacity is lower and the friction coefficient increases with the pseudo-plasticity coefficient of the lubricant. The use of pseudo-plastic fluids reduces the performance of the bearings and this reduction grows with the porous bearings.