Effects of thermodiffusion and nanoparticles on convective instabilities in binary nanofluids

Jake Kim, Chang Kyun Choi, Yong Tae Kang, Moo G. Kim

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)


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 δ4 increases for δ4 > -1. It is also found that with an increase of the volume fraction of nanoparticles, the nanofluid becomes stable, but at or near ψbf = - 0.3 the state of nanofluid changes from stable to unstable. The results from the addition factor analysis show that an asymptotic point of ψbf where the maximum value of g diverges infinitely exists in the range of - 1.2 < ψbf < - 1.1 with given conditions. The binary addition factor g is always higher than the normal addition factor f, which means that the heat transfer enhancement by the Soret effect in binary nanofluids is more significant than that in normal nanofluids.

Original languageEnglish
Pages (from-to)29-39
Number of pages11
JournalNanoscale and Microscale Thermophysical Engineering
Issue number1
Publication statusPublished - 2006 Apr 1
Externally publishedYes

Bibliographical note

Funding Information:
Received 9 August 2004; accepted 22 February 2005. This paper was supported by a Korea Research Foundation grant (KRF-2003-041-D00113) and by MOCIE through IERC program. This paper was presented at the Micro/Nanoscale Energy Conversion and Transport 2004, August 9–12 at Seoul National University, Korea. Address correspondence to Yong Tae Kang, School of Mechanical and Industrial Systems Engineering, Kyung Hee University, Seocheon-1, Yong-In, Kyung-gi, 449-701, Korea. E-mail: ytkang@khu.ac.kr


  • Binary nanofluid
  • Convective instability
  • Nanoparticles
  • Soret effect
  • Thermodiffusion

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials


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