Effect of the fractal dimension of nanoparticle aggregates on enhanced thermal transport in nanofluids – a molecular dynamics study

Abstract

ABSTRACT Equilibrium molecular dynamics simulations are employed to explore the underlying relationship between the strength of liquid layering around a nanoparticle and nanoparticle aggregation, and its effect on thermal transport in nanofluids. Results indicate that the contribution of the liquid phase to the thermal conductivity of the nanofluid is higher in the aggregated state than in the well-dispersed state. Rough aggregates with a low fractal dimension, formed in the presence of strong liquid layering, can hold a larger number of liquid atoms in the vicinity of the aggregate for an extended period compared to rounded aggregates. Additional simulations establish that a rough nanoparticle, like the aggregates of low fractal dimension, can hold a larger number of liquid atoms in the layer adjacent to it than a smooth particle of the same volume. The study indicates that the particles or aggregates of low fractal dimensions improve the thermal transport at the particle–liquid interface, leading to increased thermal conductivity.