Experimental study on thermal conductivity and electrical conductivity of diesel oil-based nanofluids of graphene nanoplatelets and carbon nanotubes

In this study the performance of diesel oil using carbon-based nano additives evaluated. Since carbon nanostructures are unstable in diesel oil (DO), covalent and noncovalent bonds can solve this challenge to a large extent. Here, nanoparticles containing graphene nanoplatelets (GNP) as well as multi-walled carbon nanotubes (MWCNT) in the form of non-covalent with surfactant oleic acid (OA) and covalent with hexylamine (HA) have been synthesized and their thermal and electrical conductivity have investigated in the laboratory. For this purpose, individually, GNP and MWCNT are functionalized with hexylamine. Then, nanofluids include HA-GNP/DO, HA-MWCNT/DO, OA-GNP/DO, OA-MWCNT/DO and a hybrid of OA-GNP and MWCNT/DO at weight concentrations of 0.05%, 0.1%, 0.2%, and 0.5% were synthesized. The thermal conductivity and electrical conductivity of above suspensions, were studied at temperatures of 5 °C to 100 °C. The results showed increasing in thermal conductivity and electrical conductivity of all nanofluids in all weight concentrations compared to the pure diesel oil at the constant temperature. In addition, with increasing temperature, thermal conductivity and electrical conductivity increased for all weight concentrations.