Thermal conductivity measurement of methanol-based nanofluids with Al2O3 and SiO2 nanoparticles

doi:10.1016/j.ijheatmasstransfer.2012.05.048

International Journal of Heat and Mass Transfer

Volume 55, Issues 21–22, October 2012, Pages 5597-5602

https://doi.org/10.1016/j.ijheatmasstransfer.2012.05.048 Get rights and content

Abstract

In this study, the methanol-based nanofluids with Al₂O₃ and SiO₂ nanoparticles are prepared by dispersing nanoparticles in pure methanol using an ultrasonic equipment. The main objective of this paper is to measure the thermal conductivity of the methanol-based nanofluids. We have also measured the zeta potential, particle size and Tyndall effect for the present nanofluids. The transient hot-wire method is applied for measuring the thermal conductivity of methanol-based nanofluids. The measurement uncertainty in repeatability is obtained as 1.95% for deionized (DI) water and 1.34% for pure methanol, respectively. The effective thermal conductivity of methanol-based nanofluids is measured at a temperature of 293.15 K. The results show that the thermal conductivity increases with an increase of the nanoparticle volume fraction, and the enhancement is observed to be 10.74% and 14.29% over the basefluid at the volume fraction of 0.5vol% for Al₂O₃ and SiO₂ nanoparticles, respectively. Clustering of nanoparticles is considered to be the main reason for the thermal conductivity enhancement.

Introduction

Ultrahigh-performance cooling is one of the most vital needs for many industrial technologies such as power generation, air conditioning, transportation, and microelectronics, due to the heating and cooling processes involved [1]. However, poor thermal conductivity is a primary limitation in developing energy-efficient heat transfer fluids that are required for ultrahigh-cooling performance. Therefore, various attempts have been made in order to enhance thermal conductivity of fluids in these fields [2], [3], [4].

One of the methods to enhance thermal conductivity is to add solid particles into the fluid in the form of suspension. However, when the particle sizes are on the order of millimeters or micrometers, the suspension is unstable due to the sedimentation occurred. Therefore, since Choi et al. [5] conceived the novel concept of nanofluids and utilized them for heat transfer enhancement, the research topic of nanofluids has been paid increasing attention world-widely.

In the past decades, a significant amount of experimental and theoretical research was investigated to understand the thermo-physical behavior of nanofluids [6], [7], [8], [9]. They observed that high thermal conductivity enhancement could be obtained by the nanofluids. The experiments also show that the thermal conductivity of nanofluids depends on many factors, such as particle material and shape, particle size, particle volume fraction, basefluid property, and temperature [4]. Deionized (DI) water, ethylene glycol and engine oil have been used as the basefluid.

In this study, the methanol is firstly to be used as a basefluid to develop nanofluids, and the nanoparticles used in the present nanofluids have been made of two types (Al₂O₃ and SiO₂). The methanol-based nanofluids can be applied for CO₂ absorption enhancement in synthetic natural gas (SNG) systems [10]. For applying the nanofluids to CO₂ absorption system, the thermal characteristics of the nanofluids should be clarified. So the main objective of this paper is to measure the thermal conductivity of methanol-based nanofluids with Al₂O₃ and SiO₂ nanoparticles. In addition, experiments on dispersion stability are carried out to investigate the characteristics of particle size, zeta potential and Tyndall effect of the methanol-based nanofluids.

Section snippets

Transient hot-wire method

The transient hot-wire technique is known to be a fast and accurate method for fluid thermal conductivity measurement [11], [12]. This work presents the application of transient hot-wire method for measuring the thermal conductivity of the methanol-based nanofluids. Pt-wire is used as the hot-wire which is coated with isonel layer to prevent the current leakage to the test suspension. The schematic diagram and test section of the transient hot-wire system are the same as described in Fig. 1,

Results and discussion

The dispersion stability, a key parameter of nanofluids characteristic, is evaluated in terms of the zeta potential, particle size and tyndall effect of nanofluids in this paper. The mean nanoparticle size and zeta potential of methanol-based nanofluids are measured by the dynamic light scattering device (ELS-Z, Otsuka, JPN). With nanoparticle volume fraction ranging from 0.005 to 0.5vol%, the measurements are carried out six times for each case.

Conclusions

In this study, the methanol-based nanofluids with Al₂O₃ and SiO₂ nanoparticles are prepared by the two-step method. The zeta potential, the particle size, the Tyndall effect and the thermal conductivity of the methanol-based nanofluids are measured. The following conclusions were drawn from the present study.

(1)
For Al₂O₃ nanofluids, the zeta potential is over 60 mV and particles size lies in 130 nm ± 10%, the dispersion stability of the methanol-based Al₂O₃ nanofluids is stated to be good. For SiO₂

Acknowledgement

This work was supported by the National Research Foundation (NRF) Grant (No. 20100029120).

References (28)

J.W. Lee et al.
CO₂ bubble absorption enhancement in methanol-based nanofluids
Int. J. Refrigerat.
(2011)
H.Y. Sul et al.
Thermal conductivity enhancement of binary nanoemulsion (O/S) for absorption application
Int. J. Heat Mass Transfer
(2011)
J.H. Lee et al.
Effective viscosities and thermal conductivity of aqueous nanofluids containing low volume concentrations of Al₂O₃ nanoparticles
Int. J. Heat Mass Transfer
(2008)
M. Elimelech et al.
Measuring the zeta (electrokinetic) potential of reverse osmosis membranes by a streaming potential analyzer
Desalination
(1994)
W. Evans et al.
Effect of aggregation and interfacial thermal resistance on thermal conductivity of nanocomposites and colloidal nanofluids
Int. J. Heat Mass Transfer
(2008)
S.K. Das et al.
Nanofluids: Science and Technology
(2007)
W. Yu et al.
Review and comparison of nanofluid thermal conductivity and heat transfer enhancements
Heat Transfer Eng.
(2008)
M. Chandrasekar et al.
A review on the mechanisms of heat transport in nanofluids
Heat Transfer Eng.
(2009)
S. Özerinç et al.
Enhanced thermal conductivity of nanofluids: a state of the art review
Microfluid Nanofluid
(2010)
S.U.S. Choi, J.A. Eastman, Enhancing thermal conductivity of fluids with nanoparticles, in: International mechanical...

S. Lee et al.

Measuring thermal conductivity of fluids containing oxide nanoparticles

J. Heat Transfer

(1999)

S.K. Das et al.

Temperature dependence of thermal conductivity enhancement for nanofluids

J. Heat Transfer

(2003)

M.J. Assael et al.

Thermal conductivity of nanofluids – experimental and theoretical

Int. J. Thermophys.

(2006)

M.P. Beck et al.

The effect of particle size on the thermal conductivity of alumina nanofluids

J. Nanoparticle Res.

(2009)

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View full text

Thermal conductivity measurement of methanol-based nanofluids with Al2O3 and SiO2 nanoparticles

Abstract

Introduction

Section snippets

Transient hot-wire method

Results and discussion

Conclusions

Acknowledgement

Int. J. Refrigerat.

Int. J. Heat Mass Transfer

Int. J. Heat Mass Transfer

Desalination

Int. J. Heat Mass Transfer

Nanofluids: Science and Technology

Review and comparison of nanofluid thermal conductivity and heat transfer enhancements

Heat Transfer Eng.

A review on the mechanisms of heat transport in nanofluids

Heat Transfer Eng.

Enhanced thermal conductivity of nanofluids: a state of the art review

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Measuring thermal conductivity of fluids containing oxide nanoparticles

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The effect of particle size on the thermal conductivity of alumina nanofluids

J. Nanoparticle Res.

Thermal conductivity measurement of methanol-based nanofluids with Al₂O₃ and SiO₂ nanoparticles