The thermal conductivity of alumina nanofluids in water, ethylene glycol, and ethylene glycol + water mixtures

Beck, Michael P.; Yuan, Yanhui; Warrier, Pramod; Teja, Amyn S.

doi:10.1007/s11051-009-9716-9

Cited by 153 publications

(60 citation statements)

References 31 publications

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“…Equation (20) shows that the equivalent thermal conductivity increases with the increase in temperature and particle concentration, which qualitatively agrees with the results in many studies [25,29,32,53,54], and part of the experimental data of these literatures are shown in Figure 4. Furthermore, the enhancement of thermal conductivity also depends on the base fluid (agrees with the results in references [26,30]), which determines dielectric constant, ion charges and ion concentrations. It should be noted that the particle mass ratio and particle charge ratio in nanofluids, instead of particle size, affect the equivalent thermal conductivity, which could explain the contradictory experimental results relevant to the influence of particle size [25,[29][30][31].…”

Section: Influence Factors Of Heat Transport In Nanofluidssupporting

confidence: 86%

“…Furthermore, the enhancement of thermal conductivity also depends on the base fluid (agrees with the results in references [26,30]), which determines dielectric constant, ion charges and ion concentrations. It should be noted that the particle mass ratio and particle charge ratio in nanofluids, instead of particle size, affect the equivalent thermal conductivity, which could explain the contradictory experimental results relevant to the influence of particle size [25,[29][30][31]. Meanwhile, Equation (20) also could explain the results in literatures [33,34] that the thermal conductivity of nanoparticles did not influence the thermal conductivity enhancement of dilute nanofluids.…”

Section: Influence Factors Of Heat Transport In Nanofluidssupporting

confidence: 86%

“…However, the effects of many factors are inconsistent in different experiments. Some studies indicated that the thermal conductivity of nanofluids increased with decreasing particle size [25,29], while other researchers showed increasing thermal conductivity with the increase of particle size [30,31]. A higher thermal conductivity of nanofluids is commonly observed with a higher thermal conductivity of the nanoparticles [32], while Shima and Philip [33] discovered that the thermal conductivity of nanoparticles did not influence the thermal conductivity enhancement of dilute nanofluids, and the thermal conductivity was solely dependent on the volume fraction of nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids

Kang

Wang

2017

Energies

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Nanofluids have an enhanced thermal conductivity compared with their base fluid. Although many mechanisms have been proposed, few of them could give a satisfactory explanation of experimental data. In this study, a mechanism of heat transport enhancement is proposed based on the cross coupling of thermal and electric transports in nanofluids. Nanoparticles are viewed as large molecules which have thermal motion together with the molecules of the base fluid. As the nanoparticles have surface charges, the motion of nanoparticles in the high-temperature region will generate a relatively strong varying electric field through which the motion will be transported to other nanoparticles, leading to a simultaneous temperature rise of low-temperature nanoparticles. The local base fluid will thus be heated up by these nanoparticles through molecular collision. Every nanoparticle could, therefore, be considered as an internal heat source, thereby enhancing the equivalent thermal conductivity significantly. This mechanism qualitatively agrees with many experimental data and is thus of significance in designing and applying nanofluids.

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Section: Influence Factors Of Heat Transport In Nanofluidssupporting

confidence: 86%

Section: Influence Factors Of Heat Transport In Nanofluidssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids

Kang

Wang

2017

Energies

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“…The nanoparticles are then dispersed into a fluid in a second processing step. Simple techniques such as ultrasonic agitation, control of pH or the addition of surfactants to the fluids are sometimes used to minimize particle aggregation and improve dispersion behavior (Beck et al 2010;Hong et al 2005;Li et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Simple glucose reduction route for one-step synthesis of copper nanofluids

Shenoy

Shetty

2012

Appl Nanosci

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One-step method has been employed in the synthesis of copper nanofluids. Copper nitrate is reduced by glucose in the presence of sodium lauryl sulfate. The synthesized particles are characterized by X-ray diffraction technique for the phase structure; electron diffraction X-ray analysis for chemical composition; transmission electron microscopy and field emission scanning electron microscopy for the morphology; Fourier-transform infrared spectroscopy and ultraviolet-visible spectroscopy for the analysis of ingredients of the solution. Thermal conductivity, sedimentation and rheological measurements have also been carried out. It is found that the reaction parameters have considerable effect on the size of the particle formed and rate of the reaction. The techniques confirm that the synthesized particles are copper. The reported method showed promising increase in the thermal conductivity of the base fluid and is found to be reliable, simple and cost-effective method for preparing heat transfer fluids with higher stability.

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“…Eastman et al (3) , 33nm Xie et al (4) , 60nm Zhang et al (5) , 20nm, T=30 o C Li et al (6) , 47nm, T=27.5 o C Beck et al (7) , 12nm, T=24-29 o C Thermal conductivity ratio(keff/kf) Volume fraction(%) Fig. 1 에 의해 다음과 같이 주어진다.…”

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Onset of Natural Convection in Transient Hot Wire Device for Measuring Thermal Conductivity of Nanofluids

Lee¹,

Kim²,

Jang

2011

Transactions of the Korean Society of Mechanical Engineers B

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We perform a numerical study to determine the time of onset of natural convection in a transient hot wire (THW) device for measuring the thermal conductivity of nanofluids. The samples used in this simulation are water-based Al 2 O 3 nanofluids with volume fractions of 1%, 4%, and 10%, and the properties are calculated by theoretical models and experimental correlations. The THW apparatus using coated wire is modeled by the control-volume-based finite difference method, and the start of natural convection is determined by observing the temperature rise of the wire under a gravity field. The onset time is 11.5 s for water and 41.6 s for water-based Al 2 O 3 nanofluids predicted by Maxwell thermal conductivity model with a 10% volume fraction. We confirm that the onset time of natural convection of nanofluids in the cylinder increases with the nanoparticle volume fraction. We suggest a correlation for predicting the onset time on the basis of the numerical results. Finally, it is shown that the measurement error due to natural convection is negligible if the measurement using the transient hot wire method is completed before the onset of natural convection in the base fluid. † Corresponding Author, spjang@kau.ac.kr

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The thermal conductivity of alumina nanofluids in water, ethylene glycol, and ethylene glycol + water mixtures

Cited by 153 publications

References 31 publications

Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids

Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids

Simple glucose reduction route for one-step synthesis of copper nanofluids

Onset of Natural Convection in Transient Hot Wire Device for Measuring Thermal Conductivity of Nanofluids

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