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Preparation and characterization of carbon nanofluid by a plasma arc nanoparticles synthesis system.

Teng TP, Cheng CM, Pai FY - Nanoscale Res Lett (2011)

Bottom Line: The particle size and shape were determined using the light-scattering size analyzer, SEM, and TEM.The thermal conductivity of carbon/water nanofluid increased by about 25% at 50°C compared to distilled water.The experimental results demonstrated excellent thermal conductivity and feasibility for manufacturing of carbon/water nanofluids.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Industrial Education, National Taiwan Normal University, No, 162, Sec, 1, He-ping E, Rd,, Da-an District, Taipei City 10610, Taiwan. tube5711@ntnu.edu.tw.

ABSTRACT
Heat dissipation from electrical appliances is a significant issue with contemporary electrical devices. One factor in the improvement of heat dissipation is the heat transfer performance of the working fluid. In this study, we used plasma arc technology to produce a nanofluid of carbon nanoparticles dispersed in distilled water. In a one-step synthesis, carbon was simultaneously heated and vaporized in the chamber, the carbon vapor and particles were then carried to a collector, where cooling furnished the desired carbon/water nanofluid. The particle size and shape were determined using the light-scattering size analyzer, SEM, and TEM. Crystal morphology was examined by XRD. Finally, the characterization include thermal conductivity, viscosity, density and electric conductivity were evaluated by suitable instruments under different temperatures. The thermal conductivity of carbon/water nanofluid increased by about 25% at 50°C compared to distilled water. The experimental results demonstrated excellent thermal conductivity and feasibility for manufacturing of carbon/water nanofluids.

No MeSH data available.


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Dependence relationship between temperatures and electric conductivity enhanced carbon/water nanofluid ratio under different fabrication parameters.
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Figure 10: Dependence relationship between temperatures and electric conductivity enhanced carbon/water nanofluid ratio under different fabrication parameters.

Mentions: Figure 10 shows the change in ratio of the nanofluid electric conductivity to distilled water at different temperatures. There is no dramatic change observed in electrical conductivity over the temperature test range of 30°C, since the temperature range is small. When the NC-70 concentration is 0.02 wt.% and the temperature of carbon/water nanofluid is in the range of 20-50°C, the change in electric conductivity ratio increases by 6.48-12.10%. For an NC-80 concentration of 0.04 wt.%, the change in electric conductivity ratio increases by 25.37-36.71%. The minimum enhanced ratios of electric conductivity for the two samples occur at 50°C. Comparing the experimental results with literature, this study used the model of Cruz et al. [35] modified from Maxwell's model [36] for analysis and comparison. Because the electric conductivity of carbon is much higher than that of the distilled water and that α is greater than one (α = (ep /ebf) ≫ 1), the principle of highly conducting particles (Eq. 9) is chosen to be compared with the experimental results of this study. Figure 10 shows a considerable underestimation while comparing calculation results with experimental data under most conditions. Because the Maxwell's model [36] is suitable only for fluids with large-size (micrometer or millimeter) particles dispersing [37-39], underestimation of the conductivity increases in nanofluid. Apart from the concentration and electric conductivity of particles and fluids, the effective electrical conductivity of nanofluids exhibits a complex dependence on the electrical double layer interactions [40,41], ionic concentrations, and other physicochemical properties which is not effectively captured by the Maxwell's model. Furthermore, this phenomenon of underestimation may result from the lower solid-liquid interface resistance due to high surface wetting of carbon nanoparticles by one-step synthesis, which results in the electric conductivity of carbon/water nanofluids with a higher enhancement.(9)


Preparation and characterization of carbon nanofluid by a plasma arc nanoparticles synthesis system.

Teng TP, Cheng CM, Pai FY - Nanoscale Res Lett (2011)

Dependence relationship between temperatures and electric conductivity enhanced carbon/water nanofluid ratio under different fabrication parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211359&req=5

Figure 10: Dependence relationship between temperatures and electric conductivity enhanced carbon/water nanofluid ratio under different fabrication parameters.
Mentions: Figure 10 shows the change in ratio of the nanofluid electric conductivity to distilled water at different temperatures. There is no dramatic change observed in electrical conductivity over the temperature test range of 30°C, since the temperature range is small. When the NC-70 concentration is 0.02 wt.% and the temperature of carbon/water nanofluid is in the range of 20-50°C, the change in electric conductivity ratio increases by 6.48-12.10%. For an NC-80 concentration of 0.04 wt.%, the change in electric conductivity ratio increases by 25.37-36.71%. The minimum enhanced ratios of electric conductivity for the two samples occur at 50°C. Comparing the experimental results with literature, this study used the model of Cruz et al. [35] modified from Maxwell's model [36] for analysis and comparison. Because the electric conductivity of carbon is much higher than that of the distilled water and that α is greater than one (α = (ep /ebf) ≫ 1), the principle of highly conducting particles (Eq. 9) is chosen to be compared with the experimental results of this study. Figure 10 shows a considerable underestimation while comparing calculation results with experimental data under most conditions. Because the Maxwell's model [36] is suitable only for fluids with large-size (micrometer or millimeter) particles dispersing [37-39], underestimation of the conductivity increases in nanofluid. Apart from the concentration and electric conductivity of particles and fluids, the effective electrical conductivity of nanofluids exhibits a complex dependence on the electrical double layer interactions [40,41], ionic concentrations, and other physicochemical properties which is not effectively captured by the Maxwell's model. Furthermore, this phenomenon of underestimation may result from the lower solid-liquid interface resistance due to high surface wetting of carbon nanoparticles by one-step synthesis, which results in the electric conductivity of carbon/water nanofluids with a higher enhancement.(9)

Bottom Line: The particle size and shape were determined using the light-scattering size analyzer, SEM, and TEM.The thermal conductivity of carbon/water nanofluid increased by about 25% at 50°C compared to distilled water.The experimental results demonstrated excellent thermal conductivity and feasibility for manufacturing of carbon/water nanofluids.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Industrial Education, National Taiwan Normal University, No, 162, Sec, 1, He-ping E, Rd,, Da-an District, Taipei City 10610, Taiwan. tube5711@ntnu.edu.tw.

ABSTRACT
Heat dissipation from electrical appliances is a significant issue with contemporary electrical devices. One factor in the improvement of heat dissipation is the heat transfer performance of the working fluid. In this study, we used plasma arc technology to produce a nanofluid of carbon nanoparticles dispersed in distilled water. In a one-step synthesis, carbon was simultaneously heated and vaporized in the chamber, the carbon vapor and particles were then carried to a collector, where cooling furnished the desired carbon/water nanofluid. The particle size and shape were determined using the light-scattering size analyzer, SEM, and TEM. Crystal morphology was examined by XRD. Finally, the characterization include thermal conductivity, viscosity, density and electric conductivity were evaluated by suitable instruments under different temperatures. The thermal conductivity of carbon/water nanofluid increased by about 25% at 50°C compared to distilled water. The experimental results demonstrated excellent thermal conductivity and feasibility for manufacturing of carbon/water nanofluids.

No MeSH data available.


Related in: MedlinePlus