Jornal de termodinâmica e catálise
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Thermophysical Properties of Copper and Silica Nanofluids in Glycerol-Water Mixture Base Liquid.

M L R Chaitanya Lahari1, P H V Sesha Talpa Sai2*, K S Narayanaswamy3, K.V. Sharma4

Thermophysical properties of copper and silica nanoparticles dispersed in glycerol-water mixture as base liquid are determined experimentally. Cu and SiO2 nanoparticles are mixed in a glycerol-water mixture of 30:70 ratio by volume. Three concentrations of 0.2%, 0.6%, and 1.0% are prepared and viscosity (µ), thermal conductivity (k), specific heat (Cp), and density (?) are determined in the temperature range of 20°C - 80°C using Brookfield Viscometer and TPS500S thermal constants analyzer. Nanofluid viscosity and density increased with particle concentration and decreased with temperature. The ‘k’ of nanofluids increased with temperature and particle concentration. Specific heat, ‘Cp’ of nanofluids reduced with volume concentration and enhanced with temperature. Maximum viscosity is observed for 1.0% Cu and SiO₂ nanofluids at 20°C and is 3.615 cP and 4.334 cP respectively against the base liquid viscosity of 3.040 cP at the same temperature. Thermal conductivity is maximum for 1.0% concentration at 80°C measured to be 0.843 W/m.K , 1.005 W/m.K for SiO₂ , Cu nanofluids whereas the base liquid thermal conductivity is 0.461 W/mK. The specific heat of Cu and SiO₂ nanofluids for 0.2% concentration at 20°C is 3432 J/kg K , 3468 J/kg K which increased to 3598 J/kg K , 3652 J/kg K at 80°C. The ‘density’(? ) of Cu and SiO₂ nanofluids of 1.0% concentration at 20°C, is computed to be 1102 kg/m3 and 1057 kg/m3 which decreased to 1089 kg/m3 and 1028 kg/m3 respectively at 80°C.