Study of the enhanced thermal conductivity of Fe nanofluids

TLDR

Nanofluids, mixtures of nanoparticles and fluid, hold great promise for enhancing heat‑transfer fluid efficiency. Fe nanofluids were fabricated by dispersing Fe nanocrystalline powder, produced via chemical vapor condensation, in ethylene glycol and then sonicated with high‑powered pulses to improve nanoparticle dispersion. Sonication increased the thermal conductivity of Fe nanofluids, with a nonlinear rise up to 18 % at 0.55 vol % particle loading, yet Fe nanofluids performed worse than Cu nanofluids, indicating that high intrinsic thermal conductivity of the particles does not guarantee superior nanofluid performance.

Abstract

Nanofluids, a mixture of nanoparticles and fluid, have enormous potential to improve the efficiency of heat transfer fluids. Fe nanofluids are prepared with ethylene glycol and Fe nanocrystalline powder synthesized by a chemical vapor condensation process. Sonication with high-powered pulses is used to improve the dispersion of nanoparticles in the preparation of nanofluids. Nanofluids exhibit an enhancement of thermal conductivity after sonication. Thermal conductivity of a Fe nanofluid is increased nonlinearly up to 18% as the volume fraction of particles is increased up to 0.55 vol. %. Comparing Fe nanofluids with Cu nanofluids, we find that the suspension of highly thermally conductive materials is not always effective to improve thermal transport property of nanofluids.