Phase Mixture Models for the Thermal Conductivity of Nanofluids and Nanocrystalline Solids

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F09%3A00021605" target="_blank" >RIV/60461373:22310/09:00021605 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Phase Mixture Models for the Thermal Conductivity of Nanofluids and Nanocrystalline Solids

Popis výsledku v původním jazyce

Nanofluids exhibit enhanced thermal conductivity with decreasing particle size, while nanocrystalline solids show a thermal conductivity reduction with decreasing grain size. Both phenomena can be modeled as being due to a boundary phase acting as a thermal bridge or barrier, respectively. In this paper a new phase mixture model is presented, based on a ?mixed average? of the upper and lower Wiener bounds. It is shown that in the case of alumina-water nanofluids our model is able to describe very well the experimentally measured data for nanofluids with 38, 25 and 13 nm alumina particles, when the solid-like boundary phase is assumed to possess ice-like thermal conductivity (2 W/mK) and a thickness of 1-5 nm. For nanocrystalline alumina (assuming a grain boundary with thickness 1 nm and a glass-like conductivity value of 1.1 W/mK), it is shown that significant grain size effects cannot be expected for grain sizes above 100 nm and a more than 10 % conductivity reduction requires grain s

Název v anglickém jazyce

Phase Mixture Models for the Thermal Conductivity of Nanofluids and Nanocrystalline Solids

Popis výsledku anglicky

Nanofluids exhibit enhanced thermal conductivity with decreasing particle size, while nanocrystalline solids show a thermal conductivity reduction with decreasing grain size. Both phenomena can be modeled as being due to a boundary phase acting as a thermal bridge or barrier, respectively. In this paper a new phase mixture model is presented, based on a ?mixed average? of the upper and lower Wiener bounds. It is shown that in the case of alumina-water nanofluids our model is able to describe very well the experimentally measured data for nanofluids with 38, 25 and 13 nm alumina particles, when the solid-like boundary phase is assumed to possess ice-like thermal conductivity (2 W/mK) and a thickness of 1-5 nm. For nanocrystalline alumina (assuming a grain boundary with thickness 1 nm and a glass-like conductivity value of 1.1 W/mK), it is shown that significant grain size effects cannot be expected for grain sizes above 100 nm and a more than 10 % conductivity reduction requires grain s

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

JH - Keramika, žáruvzdorné materiály a skla

OECD FORD obor

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Projekt

<a href="/cs/project/IAA401250703" target="_blank" >IAA401250703: PORÉZNÍ KERAMIKA, KERAMICKÉ KOMPOZITY A NANOKERAMIKA</a><br>

Návaznosti

Z - Vyzkumny zamer (s odkazem do CEZ)

Rok uplatnění

2009

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

AIP Conference Proceedings

ISSN

0094-243X

e-ISSN

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Svazek periodika

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Číslo periodika v rámci svazku

1145

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

4

Strana od-do

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Kód UT WoS článku

000270602900020

EID výsledku v databázi Scopus

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