Investigation of particle size effect on thermal conductivity enhancement of distilled water-Al2O3 nano fluids

摘要

Nano fluids are dispersions of high thermal conductivity nano particles in a basefluid, and offer potential to improve thermal conductivity of it. Literature data onthe effect of particle size on the thermal conductivity enhancement of nano fluidsare inconsistent and limited. Hence in the present study, the effect of particle sizeon thermal conductivity enhancement of distilled water- Al 2 O 3 nano fluid has beeninvestigated experimentally using transient hot wire apparatus. The particle volumeconcentration of Al 2 O 3 nano particles for mean diameter of 15nm and 60nm are variedbetween 0.1 and 3%. The enhancement in the thermal conductivity is approximately22% and 17% for 15 nm and 60nm particle size respectively, at 3% particle volumeconcentration at 30 ο C. These experimental results are consistent with the predictionsfrom the Brownian motion based model, show that the enhancement in the thermalconductivity of the distilled water- Al 2 O 3 nano fluid decreases with an increase in theparticle size.