Performance Analysis of Experimentally Characterized Titanium Dioxide and Zinc Oxide Nano-Lubricated Journal Bearing Considering Thermal and Cavitation Effects

This study is concerned with steady-state thermo-hydrodynamic performance analysis of journal bearing lubricated with experimentally characterized titanium dioxide and zinc oxide nano-lubricants using the computational fluid dynamics technique. For this purpose, nano-lubricants have been prepared by blending different weight fractions of the nanoparticles in SAE15W40 base oil. The prepared nano-lubricants are characterized by performing different experimental tests such as the X-ray diffraction, dynamic light scattering and the scanning electron microscopy. The nano-lubricants viscosities are measured by using suitable rheometer and then compared with that calculated by Krieger-Dougherty equation. The effect of aggregated nanoparticles in the prepared nano-lubricants on the nano-lubricants viscosities has been considered by evaluating the aggregate ratio which was found to be 2.4 and 2.1 for titanium dioxide and zinc oxide nano-lubricants, respectively. A three-dimensional computational fluid dynamic model has been built to analyze the thermal performance of the journal bearing using ANSYS FLUENT software. The effects of the particle weight fraction, the journal speed, bearing eccentricity ratio, and the cavitation on the thermo-hydrodynamic behavior of such bearing have been extensively studied. The obtained results show that dispersing small weight fractions of the nanoparticles in the base oil increases the load-carrying capacity by about 9-23% with a negligible increase in oil film temperature.