Traditional cooling fluids, such as water and oil, have been used in various applications over the past few decades. Due to their low thermal characteristics and latest advancement in nanotechnology, Choi et al.¹  was first to propose the concept of nanofluids by dispersing nanoparticles ranging in diameters from 1 nm to 100 nm. Since then, nanoparticles have been utilized significantly by many researchers in various areas. Such areas include conversion, energy storage, energy saving, and drug-loading nanoparticles. Several studies and reviews on increasing the thermal efficiency of thermal systems using nanofluids have been reported in the literature.^2–18  Shafahi et al.⁶  investigated numerically the thermal performance of a cylindrical heat pipe using various nanoparticles, namely Al₂O₃, CuO, and TiO₂. The findings of their study showed that the thermal performance of the heat pipe increased with the addition of the nanoparticles, related to a reduction in thermal resistance. Furthermore, the authors documented that the size of the particles was found to have a profound effect on the temperature gradient along the heat pipe. Jang and Choi⁹  investigated theoretically the effect of Brownian motion in augmenting the thermal conductivity of nanofluids. The authors claimed that they found a significant difference between solid/solid composites and solid/liquid suspensions in the size-dependent effective thermal conductivity of nanofluids. Wang et al.¹¹  developed a method to determine the effective thermal conductivity of a nanofluid using the fractal theory and the effective medium approximation. The size of the nanoparticles and the surface adsorption were considered in their study. The developed model was found to predict well the thermal conductivity of the measured values of metallic oxide nanoparticles.