Results of experimental investigations on the heat conductivity of nanofluids based on diathermic oil for high temperature applications

Colangelo, Gianpiero; Favale, Ernani; Risi, Arturo de; Laforgia, Domenico

doi:10.1016/j.apenergy.2011.11.026

Cited by 149 publications

(57 citation statements)

References 18 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: 69%

“…Generally, various factors such as temperature, base fluid, particle volume fraction, particle material, particle size and particle shape have been found to influence the thermal conductivity enhancement of nanofluids [23][24][25]. For example, the thermal conductivity increases with increasing temperature [25], and the lower thermal conductivity of based fluid, the higher thermal conductivity enhancement of the mixture [26,27]. The aspect ratio of nanoparticles and their tangling are also found to have a great influence on the thermal conductivity of nanofluids [28].…”

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: 69%

Section: Introductionmentioning

confidence: 99%

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

Kang

Wang

2017

Energies

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“…Colangelo et al [20] experimently showed that the thermal conductivity improvement of the nanofluids with diathermic oil is greater than that with water in high temperature applications such as solar collectores. They observed that the thermal conductivity reduced with increasing the size of nanoparticles.…”

Section: Role Of Base Fluidmentioning

confidence: 99%

Performance evaluation of nanofluids in solar energy: a review of the recent literature

Bozorgan

Shafahi

2015

Micro and Nano Syst Lett

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Utilizing nanofluid as an absorber fluid is an effective approach to enhance heat transfer in solar devices. The purpose of this review is to summarize the research done on the nanofluids' applications in solar thermal engineering systems in recent years. This review article provides comprehensive information for the design of a solar thermal system working at the optimum conditions. This paper identifies the opportunities for future research as well.

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“…After the pioneering works by Choi [16], Eastman et al [17], Eastman et al [18], Xuan and Li [3], and Choi et al [19], nanofluids have been extensively studied experimentally, theoretically and numerically [20][21][22][23][24][25][26][27][28]. In a recent review by Lomascolo et al [29], it has been shown that the number of annual journal publications about nanofluids has been growing exponentially.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Flow of Nanofluids in a Y-Type Intersection Channel with Multiple Pulsations: A Numerical Study

Massoudi

Yan

2017

Energies

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Abstract:In this paper, we study pulsed flow and heat transfer in water-Al 2 O 3 nanofluids in a Y-type intersection channel with two inlets and one outlet. At the two inlets, two sinusoidal velocities with a phase difference of π are applied. We assume that the shear viscosity and the thermal conductivity of the nanofluids depend on the nanoparticles concentration. The motion of the nanoparticles is modeled by a convention-diffusion equation, where the effects of the Brownian motion, thermophoretic diffusion, etc., are included. The effects of pulse frequency, pulse amplitude and nanoparticles concentration on the heat transfer are explored numerically at various Reynolds numbers. The results show that the application of the pulsed flow improves the heat transfer efficiency (Nusselt number) for most of the cases studied. Amongst the four factors considered, the effect of the frequency seems to be the most important.

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Results of experimental investigations on the heat conductivity of nanofluids based on diathermic oil for high temperature applications

Cited by 149 publications

References 18 publications

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

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

Performance evaluation of nanofluids in solar energy: a review of the recent literature

Heat Transfer and Flow of Nanofluids in a Y-Type Intersection Channel with Multiple Pulsations: A Numerical Study

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