Study of dispersion stability and thermo-physical properties of CuO-Jatropha oil-based nanolubricants

In the present study, nanoparticles of surface-modified copper oxide and Jatropha oil are used to prepare stable nanolubricants of various concentrations by a two-step method. Viscosity and thermal conductivity of nanolubricants for different concentrations of CuO ranging from 0 to 5 wt% have been experimentally measured and strong dependence of both the properties on concentration of CuO in the Jatropha oil is observed. About 40 and 10% enhancement in viscosity and thermal conductivity of nanolubricant is observed for 5 wt% concentrations of CuO and the viscosity of nanolubricant comes closer to ISO VG46 mineral oil. Stability of nanolubricants at different temperatures has been checked by measuring viscosity at regular intervals of time and it is observed that stability decreases with increase of CuO loading. The experimental data of viscosity are matched with two viscosity models proposed by different authors, but the experimental data of viscosity and thermal conductivity are observed over prediction by classical theoretical models of viscosity and thermal conductivity. Based on the experimental data, various constants of correlations are calculated for predicting viscosity of CuO-Jatropha oil nanolubricants at various concentrations and temperatures.