Influence of the Solid Particles Nanofluid on the Dynamic Behaviour of Rotor Fluid Film Journal Bearing Systems

Increasing the critical speed and reducing the dynamic response of the rotating machinery is a major challenge for researchers and engineering working on these machines, therefore several studies have appeared concerned with the issue of increasing the critical speed and reducing the dynamic response by improving the performance of fluid film journal bearings where they are an essential part for the rotating systems. Improving the performance of journal bearings depends on the properties of the lubricating oil, therefore several studies have focused on the improving of lubricant oil properties because this means improving the performance of rotating parts that are mounted on those journal bearings. This study aims to reduce the dynamic response and increase critical speed of rotor bearing systems via improving the dynamic coefficients of journal bearings by using nanofluid lubricant oil. The effect of nanofluid lubricant oil on the dynamic parameters of fluid film journal bearings and thus on the dynamic response and critical speed of rotor have been studied analytical and the results of the dynamic response has been verification numerically by using ANSYS software. The using of nanofluid lubricant oil in the journal bearing lubrication system is decreasing the dynamic response by 20.4% with the increase of the nanofluid aggregate fraction and it is decreasing by 15.5% with the increase of the nanofluid volume fraction at running speed. The maximum dynamic response is decreasing by 10.17% and 7.27% with the increase of nanofluid aggregate fraction and volume fraction respectively and the critical speed is increasing by 25.82% and 16.8% with the increase of the nanofluid aggregate fraction and volume fraction respectively. This study clearly showed that the nanofluid lubricant can be used to improve the performance of rotating machineries.