On the phononic and electronic contribution to the enhanced thermal conductivity of water-based silver nanofluids
V Karthik and S Sahoo and SK Pabi and S Ghosh, INTERNATIONAL JOURNAL OF THERMAL SCIENCES, 64, 53-61 (2013).
Nanofluids often exhibit significantly higher thermal conductivity compared to the base fluid. Contributions of the phononic and electronic thermal transport between a heat source and frequently colliding nanoparticles to the enhanced thermal conductivity have been investigated for the first time, through multi-scale modeling. Classical molecular dynamics (MD) model has been used to estimate the phononic component of thermal transport from the heat source to colliding nanoparticles. A meso-continuum model has been used to estimate the same as well as the thermal transport from heat source to colliding nanoparticle due to the combined effect of phononic and electronic mechanisms. The data on thermal pickup by colliding nanoparticles from the heat source, obtained by rationally combining the predictions of MD and meso-continuum approach, have been fed to a higher length scale stochastic model to estimate the enhancement in the conductivity. The stochastic model keeps track of Brownian movement of nanoparticles within the base fluid and the convective heat dissipation of the absorbed thermal energy of the nanoparticles to the surrounding fluid. The present multi-scale model estimates similar to 74% thermal conductivity enhancement in water-based silver nanofluid (0.1 vol%) having nanoparticles in the size range of 4-30 nm, and the results are in reasonable agreement with the experimental results reported in the literatures. (C) 2012 Elsevier Masson SAS. All rights reserved.
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