Superior thermal features of carbon nanotubes-based nanofluids - A review

Recent progresses in research on several key thermal features and potential applications of carbon nanotubes-laden nanofluids are reviewed and addressed. Besides briefing on the preparation of these nanofluids, available studies on conduction, convection and boiling heat transfers of this specific class of nanofluids are discussed in detail. Effects of different parameters such as concentration of carbon nanotube and temperature on thermal conductivity, convective heat transfer coefficient, and boiling critical heat flux are also demonstrated. It is found that despite inconsistencies among available data and inconclusive heat transfer mechanisms, substantial increase in these thermal features of carbon nanotubes-nanofluids compared to their base fluids remain undisputed. In addition to the work on specific heat and thermal diffusivity, available theoretical models and heat transfer mechanisms of this particular type of nanofluids are presented and discussed. Research on a new class of nanofluids termed as "ionanofluids" is also reported. Review reveals that ionanofluids exhibit superior thermal properties compared to their base ionic liquids and these properties further increase with increasing concentration of carbon nanotube as well as fluid temperature to some extent. Carbon nanotubes based both nanofluids and ionanofluids show great potential as advanced heat transfer fluids in many important applications. (C) 2014 Elsevier Ltd. All rights reserved.