Measurement of the thermal conductivity and heat transfer coefficient of nanofluids with single-walled nanotubes

This article is devoted to the experimental study of thermal conductivity and heat transfer of nanofluids with single-walled nanotubes. The thermal conductivity of nanofluids based on ethylene glycol, water, and isopropyl alcohol has been measured. The weight concentration of carbon tubes varied from $0.05$ to $0.5\%$. It is shown that in all cases the thermal conductivity of nanofluids increases significantly. For example, for a nanofluid based on isopropyl alcohol at a weight concentration of $0.05\%$, the excess of the thermal conductivity compared to the base liquid was $10.5\%$ and at a concentration of $0.25$ it was $51\%$. The results of measuring the heat transfer coefficient of a nanofluid based on isopropyl alcohol in a cylindrical channel are presented. The heat transfer coefficient of the nanofluid also has high values: at a tubes concentration of $0.25\%$, the heat transfer coefficient is $1.54 times higher than that of the base liquid. Along with the heat transfer coefficient, the pressure drop in the channel has been systematically studied, for which the viscosity of the nanofluids used has been previously studied.