Abstract:
This study concerns the theoretical determination of static performance of finite elasto-
hydrodynamic journal bearings lubricated by ferro-fluids with couple stresses. The
Reynolds equation that takes into account magneto elasto-hydrodynamics is derived by
use of continuity and momentum equations. The equation has been integrated locally
across the film thickness and an equation for the pressure gradient obtained as a function
of film thickness and total mass flow rate of lubricant, now the modified Reynolds
equation. The modified Reynolds equation obtained is solved simultaneously with the
energy equation numerically by the finite difference technique since they are highly non-
linear. The pressure and temperature profiles are obtained. The numerical scheme used
is implemented in MATLAB software version 7.14.0.739, so as to obtain the
approximate solutions where these solutions are represented in tables and graphs. Based
on the micro-continuum theory, and by taking into account the couple stresses due to the
microstructure additives, the effects of couple stresses on the performance of a finite
elasto-hydrodynamic journal bearings were studied. The results were obtained by
varying various flow parameters, notably couple stress parameter, magnetic coefficient
and eccentricity ratio. From the results it was found that the magnetic lubrication gives
higher pressure distribution. The results have also shown that lubricants with couple
stresses compared with Newtonian lubricants increase the pressure especially at high
eccentricity ratios. Thus it can be concluded that magnetic fluids lubricants with couple
stresses are better than Newtonian fluids. The results provide engineers with useful
information to design machine elements and bearing systems with a higher life
expectancy and efficiency.
