Abstract
We report for the first time how boron nitride (BN) nanotubes and nanospheres may effectively be used to achieve remarkable thermal conductivity Improvement of a fluid: Benefiting from high thermal conductivity and high-aspect-ratio of BN nanotubes, at a fraction of 6 vol %, the thermal conductivity of water was remarkably improved, up to similar to 2.6-times. With BN nanospheres as fillers, the viscosity of the fluid can be kept decently low and thermal conductivity can also be effectively improved. A combination of BN nanotubes and nanospheres was found to Increase the fluld's thermal conductivity while keeping its viscosity low, thus, such mixtures can be promising. fillers for highly thermo-conductive fluids. Finally, calculations based on finite element method were used to investigate the regarded nanofluids. On the basis of the results, thermal conductivity was :, estimated to be more than, or close to 200 W/mK for BN nanotubes and nanospheres, respectively.