MWCNT in PEG-400 nanofluids for thermal applications: A chemical, physical and thermal approach

The paper presents novel data on synthesis, identification and physicochemical investigation of MWCNT/PEG-400 nanofluids as potential nano-enhanced heat transfer and storage media. In the framework of our research, we studied the influence of temperature and nanoparticle concentration on thermal conductivity (k), viscosity (eta), density (rho) and isobaric heat capacity (C-p), using different techniques such as transient hot wire, rheology, oscillating U-tube, and Temperature-Modulated Differential Scanning Calorimetry (TMDSC), respectively. In order to characterize the new nano-enhanced phase change materials, several dispersions of MWCNT in PEG-400 were studied, of which the highest concentration presents enhancements in thermal conductivity and thermal diffusivity up to 12.7% and 13.5%, respectively. Different approaches were used to theoretically describe those experimental thermophysical properties as functions of temperature and MWCNT concentration. Thus, nanoparticle volume fraction dependence of relative viscosity was correlated based on Einstein, Brinkman, Batchelor, Krieger-Dougherty, Maron-Pierce and Brenner-Condiff models, while Hamilton-Crosser, Xue and Murshed models were applied for the description of thermal conductivity behaviour. (C) 2019 Elsevier B.V. All rights reserved.