Estimation of thermal conductivity of amorphous carbon nanotube using molecular dynamics simulations.

It is known that conductive heat transfer takes place from the hotter place to the colder region of a material following Fourier's law of heat conduction and as a consequence the colder region becomes progressively heated up until it reaches to the temperature of the hotter place. Based on the thermal evolution of the material the thermal conductivity can be estimated using the equation of Fourier's law of heat conduction. Present work reports estimation of thermal conductivity of an amorphous carbon nanotube on the basis of thermal evolution associated with conductive heat transfer through the nanotube using molecular dynamics (MD) simulation, which is very promising tool to characterize thermo-physical properties of individual nanosized particles. The estimated value of thermal conductivity of amorphous carbon nanotube is 0.075 W m(-1) K(-1) which is in agreement with the data reported in literature for conventional amorphous carbon and is several orders of magnitude smaller than that of crystalline carbon nanotube. The present theoretical study reveals that the thermal conductivity of amorphous carbon nanotube is similar to that of conventional amorphous carbonaceous materials and amorphous carbon nanotube is basically a heat insulating material.

A molecular dynamics-stochastic model for thermal conductivity of nanofluids and its experimental validation.

A model to predict the enhanced thermal conductivity of water based copper nanofluid on the basis of molecular dynamics simulation coupled with stochastic simulation shows for the first time that the temperature of a copper nanoparticle colliding with a heat source can rise rapidly within the short collision period (e.g., 10-50 ps) estimated by impact dynamics due to phonon transfer. Thereafter the particles undergo Brownian movement in the base fluid and transfer the excess heat in about 2 to 3 ms to the surrounding fluid resulting in an appreciable enhancement of the thermal conductivity of the fluid. Microconvection has minor contribution to the enhanced thermal conductivity of nanofluids. The predicted thermal conductivity of nanofluid and its variation with the volume fraction of the nanoparticles agree well with the present experiments, as well as, with the data reported in the literature.