Dispersion stability and thermal conductivity of modified ZnO/HFE-7100 nano-coolant.

In this work, ZnO nanoparticle was surface modified with the PFPE-acid as ligand. The modified ZnO particle size was about 30 nm measured by SEM. The modified ZnO/HFE-7100 nano-coolants with mass fractions of 0.10 % - 0.40 % were prepared and characterized, and their dispersion stabilities were evaluated by visual sedimentation
and UV spectrophotometer. Then the thermal conductivities of these nano-coolants were measured using a visualized transient hot-wire system. Results show that the thermal conductivity of the modified ZnO/HFE-7100 nano-coolants increased with the increasing mass fraction of nanoparticles and temperature, and 4.94 %-16.24 % enhancement were found compared to the base fluid. Based on the experimental data, a thermal conductivity model of nano-coolant was developed, and the deviation of the calculated thermal conductivity from the experimental value was less than ± 1.10 %.