Evaluation of clustering role versus Brownian motion effect on the heat conduction in nanofluids: A novel approach

Abstract

In this study, the temperature and viscosity-dependent methods were used to identify the main heat conduction mechanism in nanofluids. Three sets of experiments were conductedto investigate the effects of Brownian motion and aggregation. Image processing approach was used to identify detailed configurations of different nanofluids microstructures. The thermal conductivity of the nanofluids was measured with respect to the dynamic viscosity in the temperature range between 0 and 55 °C. TheResultsclearly indicated thatthe nanoparticle Brownian motion does not play a significant role in heat conduction of nanofluids, which was also supported by the observation that a more viscous sample rendered a higher thermal conductivity. Moreover, the microscopic pictures and the differences in the viscosity between theoretical and experimental valuessuggested the major role of particle aggregation and clustering.

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Comparison of mathematical models to estimate the thermal conductivity of TiO2-water based nanofluid: A review

“…Daviran et al [57] studied the effect of clustering and Brownian motion effect on the thermal conductivity of the nanofluid. It has been reported that Brownian motion does not play a significant role in thermal conductivity of nanofluid.…”

Electrical and thermal properties of insulating oil‐based nanofluids: a comprehensive overview

“…The Brownian motion also affects the thermal conductivity of nanofluids. The motion of nanoparticles itself and convection caused by Brownian motion will obviously improve the thermal conductivity [123][124][125]. Nanofluid as a new type of insulating material for transformers is a new development prospect to traditional oil-paper insulation system.…”

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