Modeling the thermal conductivity of carbon nanotube (CNT) nanofluids and nanocomposites – a fresh restart

Abstract

After two decades of discussion it seems that the model-based prediction of the thermal conductivity of carbon nanotube (CNT) nanofluids and nanocomposites has come to a dead end and needs a fresh restart, since misleading statements and claims and repeated over and over again, mainly in the current literature on CNT nanofluids. In this paper a simple but rigorous model is presented (in two variants) for predicting the thermal conductivity of CNT nanofluids and nanocomposites. The model is based on Fricke's classical Maxwell-type effective medium approximation for systems with spheroidal particles, but – in contrast to all previous models – takes into account the Molyneux bounds for describing the random orientation of the CNTs. We show that the predictions of our model are significantly lower than the corresponding predictions via Nan's model and will thus turn out to be closer to experimental data reported in the literature.