Thermal conductivity of an ethylene glycol/water-based nanofluid with copper-titanium dioxide nanoparticles: An experimental approach

Heat transfer fluid with low thermal conductivity limits the efficiency of thermal systems, such as heat exchangers, which require heat transfer fluid with high thermal conductivity. There is a demand to synthesize heat transfer fluids with high thermal conductivity. The emergence of nanoparticles has led to the development of nanofluids. Nanofluids can be classified as non-hybrid and hybrid nanofluids. This study investigated the thermal conductivity characteristics of a copper-titanium dioxide (Cu-TiO2 ) hybrid nanofluid and compared with those of a non-hybrid (Cu and TiO2 ) nanofluid. In addition, the effects of various factors (weight percentages of the nanoparticles, types of surfactants, pH values of the base fluid solution and sonication times) on the thermal conductivity of theCu-TiO2 hybrid nanofluid were studied. The thermal conductivity of theCu-TiO2 hybrid nanofluid increased in accordance with an increment in the weight percentage of the nanoparticles. The hybrid nanofluid containing 0.8 wt% of Cu-TiO2 and polyvinylpyrrolidone (PVP) as surfactant showed the highest thermal conductivity, exhibiting an improvement of 9.8% , compared to that of the base fluid.