Study on dispersion behavior and thermal conductivity of Cu-H_2O nanofluids

Dispersion and stability of Cu nanoparticles in water were studied under different pH values,different dispersant concentration by the method of zeta potential and absorbency.The thermal conductivity was measured by a Hot Disk Thermal Constants Anlyser.The results show that the pH condition and the addition of dispersant can significantly influence the stability and the thermal conductivity of Cu-H2O nanofluids.Optimizing pH value and dispersant concentration of the nanofluids result in higher zeta potential,which can lead to better dispersion behavior and higher thermal conductivity of nanofluids.Taking into account the combined effect of dispersion behavior and thermal conductivity,pH 9.5 can be selected as an operating pH,and the 0.07% SDBS can be selected as an optimizing concentration for the 0.1% Cu-H2O nanofluids.The thermal conductivity of Cu-H2O nanofluid is enhanced approximately nonlinearly with the weight fraction of the copper nanoparticle,which are greater than those calculated from Hamilton-crosser model.