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A Study on the Performance of a Magnetic-Fluid-Based Hydrodynamic Short Journal Bearing

DOI: 10.5402/2012/603460

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Efforts have been made to study and analyze the performance of a hydrodynamic short journal bearing under the presence of a magnetic fluid lubricant. With the usual assumptions of hydrodynamic lubrication, the associated Reynolds equation for the fluid pressure is solved with appropriate boundary conditions. In turn, this is then used to calculate the load-carrying capacity which results in the calculation of friction. The computed results presented in graphical form suggest that the bearing system registers an improved performance owing to the magnetic fluid as compared to the conventional lubricant. It is clearly observed that the load-carrying capacity increases nominally while the coefficient of friction decreases significantly. Besides, it is seen that the bearing can support a load even when there is no flow of lubricant. In addition, this type of study may offer an additional degree of freedom from design point of view in terms of the forms of the magnitude of the magnetic fluid. 1. Introduction Oliver [1] made a comparison between the lubricating performance of Newtonian and highly elastic liquid. It was seen that the elastic liquid induced load enhancement ratio and reduction in the coefficient of friction. Lin [2] dealt with the theoretical study of squeeze film behavior for a finite journal bearing lubricated with couple stress fluid. It was evaluated that the couple stress effects increased the load-carrying capacity significantly and lengthened the response time of the squeeze film. Kuzma [3] presented an analysis of an infinitely long journal bearing for the case of an electrically conducting fluid in the presence of a magnetic field. It was found that the bearing performance got improved due to the magnetization as compared to the case of conventional lubricant-based bearing. Chang et al. [4] considered two types of four-pad step-pocket journal bearing, lubricated with a ferromagnetic fluid. It was observed that the ferrofluid lubrication yielded higher overall bearing performance. Besides, the side leakage of the ferrofluid at both ends was found to be avoided. Nada et al. [5] derived the modified Reynolds equation based on the momentum and continuity equation for a ferrofluid under an applied magnetic field, in order to analyze the effect of using current carrying wire model in the design of a hydrodynamic journal bearing lubricated with a ferrofluid. The results concluded that the magnetic lubrication provided higher load-carrying capacity and reduced friction coefficient as compared to a conventional fluid-based bearing. Naduvinamani


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