Molecular dynamics study of the effect of different aspects of particles on thermal transport properties of nanofluids

Abstract

Developments in industrial sectors and green environment demand the efficient utilization of energy and its management in greater extents. Typical heat transfer fluids such as ethylene glycol, water, engine oil, etc. are less effective in heat transfer performance due to their lower thermal conductivity. Nanofluids are widely used in microelectronics, energy storage, nuclear cooling,etc. due to their enhanced heat transfer performance and they have become the subject of theoretical and experimental researchesover the few decades. Molecular dynamics simulation is a popular computational technique among the theoretical studies to investigate the different properties of nanofluids and in this study, thermal conductivity and viscosity of copper argon nanofluids is determined through MD simulation.Different types of nanoparticles used to make nanofluids have different shapes and thermal conductivity of nanofluids depends on the shape of the nanoparticles. Thermo-physical properties of nanofluidsalso depend on types of coating applied over the nanoparticles and surface wetting conditions of nanoparticles.Role of different shape of nanoparticles such as cylindrical, cubical and spherical, system temperature, volume fraction, different surface wetting conditions of nanoparticles and coating over the nanoparticles in enhancing thermal properties of the nanofluidsis discussed. Green Kubo method is employed to determine the thermal conductivity and viscosity of the nanofluids. Result shows that, thermal conductivity and viscosity of nanofluid increases with the increase of volume fraction of the nanoparticles. With the increase of system temperature, thermal conductivity of the nanofluid increases while the viscosity shows a decreasing trend. Thermal conductivity and viscosity of the nanofluid increase with the decrease of nanoparticle size. Both thermal conductivity and viscosity of the nanofluid system containing cylindrical particle is higher than that of cubic and spherical particle. Thermal conductivity enhancement of nanofluid with hydrophilic surface wetting condition is greater than the hydrophobic surface wetting condition. Thermal conductivity containing coated particle shows greater enhancement than the non-coated particle. The mechanism of increased heat transfer performance of nanofluidfor different volume fraction, temperature, different shape and size of the nanoparticles, coated over the nanoparticles and different surface wetting conditionsis discussed.