Effects of Thermodiffusion and Nanoparticles on Convective Instabilities in Binary Nanofluids
Authors: Kim, Jake1; Choi, Chang1; Kang, Yong2; Kim, Moo3
Source: Microscale Thermophysical Engineering, Volume 10, Number 1, January-March 2006 , pp. 29-39(11)
Publisher: Taylor and Francis Ltd
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Abstract:
In this article, the effects of thermodiffusion of nanoparticles and solute in binary nanofluids and nanoparticles on the convective instabilities of a binary nanofluid is theoretically investigated. Thermodiffusion implies that mass diffusion is induced by thermal gradient, which is the so-called Soret effect. In order to analyze the convective instabilities of a binary nanofluid, a new stability criterion is obtained based on the linear stability theory and new factors g and f are proposed. The results show that the Soret effect of solute makes the binary nanofluids unstable significantly and the convective motion in a binary nanofluid sets in easily as the ratio of Soret coefficient of nanofluid to that of binary basefluid δ 4 increases for δ 4 > − 1 . It is also found that with an increase of the volume fraction of nanoparticles, the nanofluid becomes stable, but at or near ψ bf = − 0.3 the state of nanofluid changes from stable to unstable. The results from the addition factor analysis show that an asymptotic point of ψ bf where the maximum value of g diverges infinitely exists in the range of − 1.2Keywords: binary nanofluid; convective instability; Soret effect; nanoparticles; thermodiffusion
Document Type: Research article
DOI: 10.1080/10893950500357772
Affiliations: 1: School of Chemical Engineering, Seoul National University, Seoul, Korea 2: School of Mechanical and Industrial Systems Engineering, Kyung Hee University, Kyung-gi, Korea 3: School of Mechanical and Automotive Engineering, Inje University, Kyongnam, South Korea
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