Abstract
The present study aims at nanoparticles characterization and stability as well as the thermal conductivity of the hybrid nano-oil of ZnO-MWCNT/oil at the temperature range from 25 to 65 degrees C and the concentrations range from 0.50 to 3.2% for the solid particles. First, the nanoparticles of MWCNT and ZnO were characterized using XRD-FESEM and FTIR tests, and according to the results, the analysis of atomic, surface and chemical structure of nanoparticles was made. The nanolubricant was prepared by a two-step method. For this purpose, firstly, the stability was analyzed by the DLS test and the results show that the nanoparticles are in nanoscale after the construction of nano-oil. The thermal conductivity was measured based on the variables of temperature and volume fraction. An increasing trend was observed for the thermal conductivity for higher temperature and volume fraction of the nanoparticles. The biggest improvement of the thermal conductivity compared to the base fluid is at 65 degrees C, the volume fraction is 3.2%, and its value is 35.1%. Moreover, a very accurate experimental relationship was developed to determine the ratio of the thermal conductivity of nano-oil in the empirical range.