On the temperature effect of nanofluid thermal conductivity by molecular dynamics simulation

Nanofluids are a new class of nanotechnology-based heat transfer fluids that possess extraordinarily high thermal conductivity and flow stability. However, the deep mechanism for the strengthened conduction heat transfer in nanofluids has not yet been fully disclosed. This study investigated the thermal conductivities of water-based nanofluids by molecular dynamics simulations and examined possible reasons for the thermal conductivity enhancement from microscopic view. By establishing water-based nanofluids simulation models with copper nanoparticles installed, the simulations were performed under different temperature conditions. It was found that the thermal conductivity is a monotonic increasing function of thermodynamic temperature. By adding 1nm copper nanoparticle, the thermal conductivity of nanofluids is increased by more than 30%. By tracking the evolution of simulation system, it was concluded that multiple factors may be responsible for the conduction heat transfer enhancement in nanofluids. Fast heat transferring through the water molecules absorbed to the nanoparticles surface, as well as micro convection effect caused by the intense motions of nanoparticles are the most likely mechanisms.