Experimental investigation on thermo physical properties of single walled carbon nanotube nanofluids

This experimental study is aimed to measure and analyze the thermal conductivity, viscosity, and specific heat of water based single walled carbon nanotube (SWCNT) nanofluids in presence of sodium dodecyl sulfate (SDS) surfactant. The surfactant was used to prepare stable nanofluids and the stability of SWCNT nanofluids of five volume concentrations (0.05-0.25 vol%) is observed good. The measured values of thermal conductivity in the range of 0.615-0.892 W/m K, viscosity in the range of 0.67-1.28 mPa s, and the specific heat in the range of 2.97-3.90 kJ/kg °C, were observed for temperature rising from 20 to 60 °C with an interval of 10 °C as the volume concentration increased from 0.05 to 0.25 vol%. The maximum thermal conductivity enhancement of 36.39% compared to water is observed for 0.25 vol% at 60 °C. The viscosity of SWCNT nanofluids exhibited a non-Newtonian shear-thinning behavior due to the alignment of nanotube clusters and agglomerates with increasing shear rate. The temperature and volume concentrations have effect on specific heat as well and it decreases with particle loadings while increases with temperature.