ON THE PERFORMANCE OF NARROW POROUS JOURNAL BEARING LUBRICATED WITH COUPLE STRESS FLUID

In the present analysis an attempt has been made to study the performance characteristics of a narrow porous journal bearing lubricated with couple stress fluid. A modified form of Reynolds equation is derived for the lubrication of porous journal bearings with couple stress fluid as lubricant. The analysis takes into account the velocity slip at the surface of a porous medium by using Beavers-Joseph criterion. The governing equation for flow in the porous media and the modified Reynolds equation derived from the Stokes [1] constistutive equations for the couple stress fluid satisfying the velocity slip boundary condition, are solved analytically for the film pressure distribution. Eigen type of expansions for the field variations are obtained. The dimensionless load capacity, attitude angle and coefficient of friction are presented for different operating parameters. The effect of couple stress and velocity slip on the dynamic characteristics of narrow porous journal bearings are discussed. It is observed that the bearings with couple stress fluid as lubricant provide significant load carrying capacity and ensure considerable reduction in the coefficient of friction compared with viscous lubricants.