An explanation of the Al2O3 nanofluid thermal conductivity based on the phonon theory of liquid. (1st December 2016) - Iacobazzi, Fabrizio
Abstract: In the present work a systematic investigation on several mechanisms affecting the thermal conductivity of Alumina based nanofluid, such as layering, Brownian motion, clustering, ballistic phonon motion, thermal boundary resistance and mass difference scattering, is presented. The effect of mass difference scattering is for the first time suggested and studied in the present work. Both theoretical and experimental approaches have been carried out in order to analyze the competition of these phenomena and to identify the most relevant. This was obtained by comparing micrometric and nanometric particles suspended in liquid water (293 K), frozen water (253 K) and diathermic oil (293 K). Each of the above-mentioned conditions was selected to make dominant only one of the mechanisms that affect nanofluid thermal conductivity. The main results of this investigation concern the mass difference scattering, which has been found to be the most intensive mechanism reducing the nanofluid thermal conductivity with respect to the microfluid one. Highlights: An investigation on mechanisms affecting thermal conductivity of Al2 O3 nanofluid has been studied. The phonon theory of liquid has been applied. Nanofluid based on liquid water, frozen water and diathermic oil has been experimentally compared. The effect of mass difference scattering is for the first time suggested and studied in the present work.