Thermal conductivity of nanofluids

The enhancement of the thermal conductivity of various heat transfer liquids, such as water, ethylene glycol and vacuum oil, in the presence of nanoparticles and carbon multiwalled nanotubes (C-MWNT) has been investigated. The nanoparticles employed were copper nanospheres and nanodiamonds. Sodium dodecyl sulfate (SDS), thioglycolic acid (TGA), and Triton X-100 were used as dispersants. The thermal conductivity was measured with a transient hot-wire instrument built for this purpose, and operated with a standard uncertainty better than 2%. The maximum thermal conductivity enhancement obtained was 38%, for a 0.6% vol. suspension of C-MWNT in water with 0.1% wt. SDS. All measurements were made at ambient temperature.