Study of the enhanced thermal conductivity of Fe nanofluids

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.