Modeling the Effect of Agglomeration in Nanoparticle Coolant Systems Using Dynamic Light Scattering.

摘要

The objective of this research was to investigate Nanofluids as new class of heat transfer fluids. Nanofluids were characterized using Dynamic Light Scattering (DLS) by obtaining volume fraction of aggregated nanoparticles as a function of aggregate radius. This data was used as an input to three analytical models to compute the overall thermal conductivity of the nanofluid. Stability analysis on alumina nanofluid (1% by vol.) indicated that the formation of aggregates was limited by diffusion and was primarily confined to the nanometer size range. A comparative study between dilute and regular alumina nanofluids concluded that the relationship between nanoparticle concentration and enhancement in thermal conductivity is nearly linear at both concentration regimes. Experiments on alumina nanofluids with 1% to 5% by volume concentration provided thermal conductivity enhancement up to 35%. This result concludes that aggregation of nanoparticles play a critical role in enhancement of thermal conductivity in nanofluids.