Colloidal Fe3O4 nanoparticles-based oil blend ferro-nanofluid for heat transfer application

The thermal conductivity enhancement of oil blend-based ferro-nanofluids for heat transfer application is rarely reported. Herein, highly stable ferro-nanofluids were prepared by dispersing oleic acid coated Fe3O4 NPs into the blend of sunflower oil and mineral oil at varying volume ratios. The maximum thermal conductivity enhancement of similar to 91% was obtained for M10 (base fluid) oil blend-based ferro-nanofluid at 0.6 vol% of Fe3O4 NPs as compared to the pure mineral oil. The dispersed NPs into the oil blend-based ferro-nanofluid executed Brownian motion which led to the collisions between the NPs as well as with the molecules of the oil blend. The formation of a chain like network by small-sized NPs effectively led to a larger volume fraction of NPs, which caused the enhancement of the thermal conductivity of oil blend-based ferro-nanofluids. Moreover, a nano-adsorption layer of oil blendwas formed on the surfaces of NPs, which served as a bridge for the heat exchange between NPs and oil blend. The experimental results were validated against a similar preexisting thermal conductivity enhancementmodel. Hence, this study provides amore efficient method to prepare oil-based ferro-nanofluids with a tunable thermal conductivity for heat transfer applications.

Automated summary

A highly stable ferro-nanofluid was prepared by dispersing Fe3O4 NPs in a blend of sunflower oil and mineral oil, resulting in a significant enhancement of thermal conductivity. The Brownian motion of the dispersed NPs and the formation of a chain-like network contributed to the enhanced thermal conductivity of the oil blend-based ferro-nanofluid. This study offers an efficient method for preparing oil-based ferro-nanofluids with tunable thermal conductivity for heat transfer applications.