Thermal Conductivity of Nanofluid With Cylindrical Nanoparticles

The addition of nanoparticles to a base fluid is an effective strategy to achieve a higher thermal conductivity of a fluid. Usually, previous theoretical investigations are focusing on spherical particles, but most real nanoparticles are definitely nonspherical particles. In this paper, the nanofluids with cylindrical nanoparticles was studied, by which the thermal conductivity could be further enhanced in contrast with a nanofluid with spheres. By using equilibrium molecule dynamics (MD) simulations, the thermal conductivity of a nanofluid with cylindrical nanoparticles was investigated. With varying height-diameter ratio of the cylindrical nanoparticle (from disks to rods), it is found that the thermal conductivity of the nanofluid decreases with the height-diameter ratio prior to reaching a minimum value, and increases with the height-diameter ratio after a critical height-diameter ratio. The underlying mechanism of the enhanced thermal conductivity was investigated based on the calculation of the solid-liquid radial distribution function (RDF) and diffusion coefficient of the nanofluids. It is found that the enhanced RDF results in the enhanced effect of the solid-like liquid layer around the nanoparticle, which in turn suppresses the solid-liquid interfacial thermal resistance and also increases the local thermal conductivity of the liquid around the nanoparticle. Therefore, the thermal conductivity of the nanofluids with cylindrical nanoparticles can be enhanced. The results obtained in the present work are helpful for understanding the influence of shape of nanoparticles on the thermal conductivity of nanofluid.