...FINITE ELEMENT ANALYSIS OF POROUS SLIDERS WITH NON-NEWTONIAN LUBRICANTS

Abstract

During the recent years lubrication engineers- have shown an increasing interest in the theoretical and experimental research on the performance of fluid film bearings with non-Newtonian lubricants. Many research papers taking different typos of non-Newtonian lubricants and their mathematical model have boon reported. In this thesis, a comparatively now type of problem concerned with the porous bearing lubrication using non-Newtonian lubricants is being taken up. The flow fields of the porous bearing lubrication are governed by a modi-fied form of Reynolds equation and the Laplace equation. In order that the same equations may directly be used for the present problem, an assumption has boon made that the viscosity at any point in the fluid film is determined by the value of shear strain rate averaged out across the film. Further the fluid viscosity in the porous matrix is assumed to be sane as in the fluid film. The shear strain rate and also the viscosity of non-Newtonian lubricant of any point in fluid film depends on the velocity profile across the film and hence on the press-ure distribution. Thus with non-Newtonian lubricant the Reynolds equation itself becomes nonlinear. The solution of the equation of the flow field has been obtained by finite element method using the method of iv weighted residuals using Galorkin's technique. To solve the nonlinear Reynolds equation an iteration scheme has been developed which has been found to be very fast conv~: rging. The results reported in this thesis are for a plane inclined slider only. A wide range of the geometric parameters of the slider has been taken and two types of constitutive relation of the non-Newtonian lubricants covering pseudoplastic as well as daila.tant region have beer used. Three typos of studies namely nonporous slider, porous slider without slip and porous slider with slip have been made. The analysis is general and can easily be adapted for any type of bearing configuration.