Tribology Online (Aug 2015)
Static Analysis of Finite Hydrodynamic Journal Bearing in Turbulent Regime with Non-Newtonian Lubricant
Abstract
The aim of the present paper is to investigate and predict the static performance of finite journal bearing in turbulent flow condition considering non-Newtonian lubrication. The Navier-Stokes equation has been modified considering turbulent as well as non-Newtonian lubrication and is solved for steady state parameters. Ng and Pan’s linear turbulence model is utilised in the analysis. The momentum and continuity equations in cylindrical coordinates representing the flow field in the clearance space of a finite circular journal bearing using a Newtonian lubricant were solved by the finite element method. The non-Newtonian lubrication effect is introduced by modifying the viscosity term using the cubic shear stress law in each iteration. In this paper, the effect of turbulence and non-Newtonian lubrication has been determined by solving the modified Navier-Stokes equations obtained by the application of linear theory proposed by Ng and Pan and using the cubic shear stress law model simultaneously. The modified Navier-Stokes equations, in cylindrical coordinates, have been solved by finite element method using Galerkin's technique and a suitable iteration procedure. Steady-state performance characteristics of a finite circular journal bearing have been analysed in terms of Sommerfeld number, load carrying capacity, friction coefficient variable, temperature rise parameter and total flow at various eccentricities for different Reynolds numbers up to 13300 and various values of non-linear factor of cubic shear stress law of non-Newtonian model. Computed results have been compared with the published results obtained by linearized theory of Ng and Pan and cubic shear stress law of non-Newtonian lubrication. The results obtained revealed better performance in turbulent regime as compared to laminar condition for cubic shear stress non-Newtonian model.
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