Analysis of Magneto Rheological Fluid Journal Bearing

Magneto Rheological (MR) fluids are a class of smart materials where the shear stress is not directly proportional to rate of shear. The viscosity of fluid changes as magnetic field changes and hence this phenomenon is very useful in bearing-rotor system for attenuating the vibrations. In the present study the application of MR fluid as lubricant instead of Newtonian fluid in the journal bearing is explored through steady state, dynamic characteristics and stability. MR fluid film has been modeled as per Bingham rheological model. FEM with three node triangular elements has been used to solve the Reynolds equation both for the Newtonian fluid film and MR fluid film. The results show the load carrying capacity in the case of MR fluid journal bearing is higher than that of using the Newtonian fluid. The load carrying capacity increases with the increasing magnetic field for all eccentricity ratios. The results also show better stability of the bearing using MR fluid at higher eccentricity ratios. The unbalance response of the rotor mounted on the journal bearing using MR fluid is also estimated to be lower than that of with the Newtonian fluid.