Analysis of shape dependency of thermal conductivity of silver-based nanofluids

Nanofluids are a class of fluids prepared by dispersing nanoparticles in conventional base fluids. Owing to their excellent thermo-physical properties, nanofluids find potential applications in manufacturing industries. They are introduced to overcome the limitation with using traditional base fluids like water having low thermal conductivity (~ 0.612 W/mK at room temperature). The thermal conductivity of a base fluid is considerably increased by adding a modest number of nanoparticles to it. In the present work, we have prepared silver nanoparticles and nanorods using the simple chemical reduction method. UV–Visible spectroscopy and field emission scanning electron microscopy were used to investigate the optical characteristics and morphology of the produced nanomaterials. Furthermore, the effect of volume loadings of produced nanomaterials (0, 2%, 4%, 6%), as well as temperature on the thermal conductivity of the base fluids was investigated. The results are compared to different silver nanoparticles (AgNPs) loadings in the base fluid. Both silver nanoparticles and nanorods have optimal heat conductivity at 2 vol%. It is interesting to note that fluids with silver nanorods (AgNRs) portrayed better results compared to nanoparticles and the maximum enhancement observed of 78.4% for AgNRs-based nanofluids at temperature 323 K, which is very high when compared to most of the previously reported values. Graphical abstract