Study on thermal transport behavior of magnesium oxide (MgO) nanostructures as lubricant additives in vegetable oils

Due to harmful impact of petroleum-based fluids and lubricants on the environment and Mankind, vegetable oil-based fluids with incorporation of eco-friendly nanostructures have a great potential to be an alternative lubricant if it possesses proper thermal transport and physico-chemical characteristics. In this study, thermal conductivity, and viscosity performance of vegetable nanolubricants, developed from soybean oil and sunflower oil, modified with homogeneous dispersion of magnesium oxide (MgO) nanostructures were evaluated at various filler fractions (0.01, 0.05, 0.10 and 0.25 wt%) over diversetemperatures. For thermal conductivity evaluation, a transient hot wire (THW) methodology was employed. It is observed that for MgO nanolubricants, thermal conductivity increased as a filler fraction and temperature were increased, reaching a maximum of 22% improvement at 0.25 wt% reinforcement at 50 °C. On the other hand, the viscosity showed a consistent behavior as a function of nanostructures filler fraction and decreased significantly in response to increased evaluating temperature. Graphical abstract: [Figure not available: see fulltext.]