Viscosity and thermal conductivity measurements of water-based nanofluids containing titanium oxide nanoparticles

Nanofluids, i.e. suspensions of nanoparticles in liquids, seem to be very promising as thermal vectors in systems where secondary fluids are applied. Here, the characterisation of water-based nanofluids containing titanium oxide (TiO2) in concentrations ranging between 1 and 35% in mass is presented. First of all, the mean nanoparticle diameters are studied by dynamic light scattering (DLS) technique and the nanofluid stability is analysed by Zeta potential measurements. Then, the behaviour of viscosity as a function of composition and temperature is evaluated by means of a rheometer, in the temperature range between 283 K and 343 K. Furthermore, the thermal conductivity of these nanofluids is measured, in order to understand its possible enhancement as a function of temperature and nanoparticle concentration.

► Water-based nanofluids with TiO2 at 1 wt%, 10 wt%, 20 wt% and 35 % were studied. ► Viscosity and thermal conductivity was measured. ► All the nanofluids exhibited a Newtonian rheological behaviour. ► The thermal conductivity increased with mass concentration and with temperature. ► The nanofluids thermal properties make them suitable for heat transfer applications.