Effects of Preload, Speed and Eccentricity Ratio of Rotor on the Thermohydrodynamic Performance of Two Lobe Journal Bearings

Due to the growing use of oil journal bearings, as an effective support for the rotating parts of industrial machines, analysis of their performance is of importance. The shear stresses and the frictional forces, proportional to the speed of the lubricant layers in different points of the bearing clearance space, causes variation in the temperature of the lubricant, journal and bearing shell. However the bearing design parameters also have effects on the lubricant temperature. So, in the present work, the effects of design parameters such as the journal speed and the preload factor of the noncircular lobe journal bearing on the temperature variations which result in variation of the pressure distribution of the lubricant as well as changes in the load carrying capacity and attitude angle of the noncircular two lobe journal bearings are investigated. Then the bearing performance parameters are calculated using the final thermal pressure distribution of lubricant. Comparing the performance of two lobe bearings, with the thermal effects and without them, shows that the lubricant viscosity and the pressure distribution in the bearings decreases by increasing the rotational velocity of the journal. Also the results indicate that the effects of lubricant temperature changes on the bearing performance decreases by increasing the amount of the bearing preload.