Özet:

Hydrostatic journal bearings are recommended for supporting shafts operating at high speeds and under heavy loads in the industry. In the journal bearings, lubricant viscosity decreases with increasing temperature at high rotation speeds and hence, the fluid between the surfaces should be circulated by means of a pump in order to cool the lubricant. However, lubricant supplying between the surfaces at the high flow rate causes the whirl instability and vibrations problems in the bearing-shaft system. These instability problems give rise to significant damage on the system during operating at the high speeds and under the heavy loads. As a solution of this problem, it could be suggested to control the variation of the lubricant viscosity with respect to the temperature by adding nanoparticle. In the present work, the effects of the lubricant with nanoparticle additives on the load performance of a hydrostatic journal bearing are theoretically investigated. The fluid film flow between the bearing and rotor surfaces are modelled with Reynolds equation and viscosity term in Reynold’s equation is defined as a function which is depends on the nanoparticle properties. Then, the pressure distribution of the bearing is obtained with numerically solving the Reynolds equation and the load capacity is calculated for different nanoparticle parameters with using this pressure distribution. The results show that the usage of the lubricant with nanoparticle increase the load performance of the hydrostatic journal bearing.

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