An anisotropic thermal conductivity model for CNTs nanofluids by considering the discontinuity of nanotubes in thermal conduction path

Abstract

A new model for the thermal conductivity (TC) of CNTs nanofluids is established by anisotropic analysis and considering the discontinuity of distribution of carbon nanotubes in thermal conduction path. When assuming that the CNTs are uniformly distributed in entire area of the nanofluids and form a network structure to conduct heat, an anisotropic thermal conductivity model can be built. However, the model only consider the anisotropy characteristic will seriously over-predict for high TC particles and hence is not suitable for CNTs nanofluids. Therefore, in this paper, the TC in a random direction is derived and then was further modified by considering the discontinuity of nanotubes in actual thermal conduction path which is related to the concentration and aspect ratio. The model showed good adaptability for the TC predictions of CNTs nanofluids, since the renovated models considering factor of concentration and aspect ratio have been verified with 10 groups of experimental data, and all the errors are less than 8%.