### 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 - 1.2 < ψ_{bf} < - 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 language | English |
---|---|

Pages (from-to) | 29-39 |

Number of pages | 11 |

Journal | Nanoscale and Microscale Thermophysical Engineering |

Volume | 10 |

Issue number | 1 |

DOIs | |

Publication status | Published - 2006 Apr 1 |

Externally published | Yes |

### Fingerprint

### Keywords

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

### ASJC Scopus subject areas

- Condensed Matter Physics
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Mechanics of Materials

### Cite this

*Nanoscale and Microscale Thermophysical Engineering*,

*10*(1), 29-39. https://doi.org/10.1080/10893950500357772

**Effects of thermodiffusion and nanoparticles on convective instabilities in binary nanofluids.** / Kim, Jake; Choi, Chang Kyun; Kang, Yong Tae; Kim, Moo G.

Research output: Contribution to journal › Article

*Nanoscale and Microscale Thermophysical Engineering*, vol. 10, no. 1, pp. 29-39. https://doi.org/10.1080/10893950500357772

}

TY - JOUR

T1 - Effects of thermodiffusion and nanoparticles on convective instabilities in binary nanofluids

AU - Kim, Jake

AU - Choi, Chang Kyun

AU - Kang, Yong Tae

AU - Kim, Moo G.

PY - 2006/4/1

Y1 - 2006/4/1

N2 - 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.

AB - 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.

KW - Binary nanofluid

KW - Convective instability

KW - Nanoparticles

KW - Soret effect

KW - Thermodiffusion

UR - http://www.scopus.com/inward/record.url?scp=33744985805&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33744985805&partnerID=8YFLogxK

U2 - 10.1080/10893950500357772

DO - 10.1080/10893950500357772

M3 - Article

VL - 10

SP - 29

EP - 39

JO - Nanoscale and Microscale Thermophysical Engineering

JF - Nanoscale and Microscale Thermophysical Engineering

SN - 1556-7265

IS - 1

ER -