Heat transfer properties of transformer oil-based nanofluids filled with Al2O3 nanoparticles

This paper is concerned with the heat transfer properties of transformer oil suspensions of Al₂O₃ nanoparticles. Nanofluids are prepared by mixing and dispersing of nanoparticles with the base oil using magnetic stirrer and ultrasonic homogenizer. To decrease the effect of van der waals attraction force between nanoparticles and improve the stability of resultant nanofluids, a surfactant is used. The used surfactant is sodium dodecyl benzene sulfonate (SDBS). The heat transfer coefficient was measured at different concentrations of nanoparticles starting from 0.1 g/L to 0.6 g/L. The results were obtained at two different weight percents of the surfactant with respect to nanoparticles (0.1% and 1%). It is found that heat transfer coefficient has a great dependence not only on nanoparticles concentration but also on weight percents of the surfactant. Based on the obtained results, the corresponding mechanisms were proposed taking into consideration the role of surfactant and the effect of nanoparticles.