Study of the Effects of Pressure Dependent Viscosity on the Lubrication Characteristics of Bearings

Abstract

In this thesis, the theoretical analysis of effect of couple stresses with piezo-viscous newlinedependency for different squeeze film bearings have been carried out with the help of stokes newlinemicro continuum theory. An approximate analytical solution is found using a small perturbation newlinemethod. The expressions for pressure and load carrying capacity and squeeze film time are newlinederived using the Reynolds s equation. For distinct values of couple stress parameter, pressure newlinedependent viscosity parameter are calculated and compared with Newtonian lubricants and the newlineresults reveals that the effect of couple stresses and pressure dependent viscosity variation newlineenhances the pressure, load-carrying capacity and lengthen the squeeze film time. newlineThe modified Reynolds equations are obtained for one dimensional two roughness patterns, newlinenamely radial roughness pattern and Azimuthal roughness pattern. The results have been newlinepresented numerically. It is observed that the effect of radial (azimuthal) roughness pattern on the newlinebearing surface decrease (increase) the pressure, load carrying capacity, and squeeze film time. newlineUsing Christensen s stochastic approach, Darcy s formula, Stokes theory and Barus formula, newlinemodified Reynolds equation is derived which is highly non-linear. Perturbation technique is used newlineto make it linear and closed form expressions for pressure, load carrying capacity and squeezing newlinetime are derived. The results are presented graphically. Also to demonstrate the accuracy it is newlinecompared with earlier works and the results are in excellent agreement with limiting cases of newlineiso-viscous non permeable bearings and piezo-viscous non-permeable bearings. newline