Temperature-dependent effect of percolation and Brownian motion on the thermal conductivity of TiO2-ethanol nanofluids

Chien Cheng Li, Nga Yu Hau, Yuechen Wang, Ai Kah Soh, Shien Ping Feng

Research output: Contribution to journalArticleResearchpeer-review

11 Citations (Scopus)

Abstract

Ethanol-based nanofluids have attracted much attention due to the enhancement in heat transfer and their potential applications in nanofluid-type fuels and thermal storage. Most research has been conducted on ethanol-based nanofluids containing various nanoparticles in low mass fraction; however, to-date such studies based on high weight fraction of nanoparticles are limited due to the poor stability problem. In addition, very little existing work has considered the inevitable water content in ethanol for the change of thermal conductivity. In this paper, the highly stable and well-dispersed TiO2-ethanol nanofluids of high weight fraction of up to 3 wt% can be fabricated by stirred bead milling, which enables the studies of thermal conductivity of TiO2-ethanol nanofluids over a wide range of operating temperatures. Our results provide evidence that the enhanced thermal conductivity is mainly contributed by the percolation network of nanoparticles at low temperatures, while it is in combination with both Brownian motion and local percolation of nanoparticle clustering at high temperatures.

Original languageEnglish
Pages (from-to)15363-15368
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume18
Issue number22
DOIs
Publication statusPublished - 14 Jun 2016

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