Thermal conductivity of water and ethylene glycol nanofluids containing new modified surface SiO2-Cu nanoparticles: Experimental and modeling

In the present study SiO2-Cu nanocomposites are synthesized and characterized. At the next stage the thermal conductivity of the SiO2-Cu/water and SiO2-Cu/EG nanofluids are measured and reported. The results show that chemical deposition of a small amount of Cu on the SiO2 surface results in considerable rise in thermal conductivity of the base fluid. A water nanofluid contains less than 1% of modified nanocomposites can increase the thermal conductivity of water up to 11%. The increment on thermal conductivity of the EG with the same amount of nanoparticles was about 11.5% (temperature 25 degrees C). One of the most important features of this work is that this type of nanofluids contains particles which have a density close to SiO2 but a thermal effect similar to copper. Finally, a core-shell model has been presented for the thermal conductivity prediction. (C) 2016 Elsevier Ltd. All rights reserved.