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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.


Related in: MedlinePlus

Dependence relationship between temperatures and viscosity enhanced ratio of carbon/water nanofluid under different fabrication parameters.
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Figure 9: Dependence relationship between temperatures and viscosity enhanced ratio of carbon/water nanofluid under different fabrication parameters.

Mentions: The viscosity of the carbon/water nanofluid as a function of shear rate, between 20°C and 50°C is shown in Figure 8. The viscosity of the carbon/water nanofluid is dependent on the shear rate over the entire measured temperature range. The addition of as little as 0.02 wt.% (NC-70) or 0.04 wt.% (NC-80) carbon nanoparticles to the distilled water results in carbon/water nanofluid displaying non-Newtonian behavior (shear thinning). Carbon/water nanofluids display Newtonian behavior with higher shear rate (SR>350 s-1), but the temperature of NC-80 is greater than 40°C. Additionally, the rheological properties of carbon/water nanofluid approach Newtonian behavior and increase carbon/water nanofluid concentrations at low temperatures. This trend occurs because viscosity reduces as water temperatures increase, so the added nanoparticles will increase the fluid internal shear stresses that results to the observed nanofluid viscosity. Adding more nanoparticles would produce a similar effect. Figure 9 shows the change in viscosity ratio for carbon/water nanofluids compared to distilled water at various temperatures and under different process parameters. In general, nanofluid viscosity increases with increasing nanoparticle loading in the bulk liquid. For an NC-70 concentration of 0.02 wt.% and within a temperature range of 20-50°C, the viscosity ratio increases by 7.77-15.17%. For an NC-80 concentration of 0.04 wt.%, the viscosity ratio increases by 15.76-31.63%. In addition, Figure 9 shows the calculated results of Einstein's model [33] (Eq. 8) in comparison with the experimental results that show a serious underestimation, which may be results from the material properties and aggregation of carbon nanoparticles [34]. From the above results, it can be found that the viscosity of carbon/water nanofluid is much higher than that of the water. When the carbon/water nanofluid was applied to heat exchange, pressure drop of pipeline and energy consumption of pump-related issues must be considered in particular in the future.(8)


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 viscosity enhanced ratio of carbon/water nanofluid under different fabrication parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 9: Dependence relationship between temperatures and viscosity enhanced ratio of carbon/water nanofluid under different fabrication parameters.
Mentions: The viscosity of the carbon/water nanofluid as a function of shear rate, between 20°C and 50°C is shown in Figure 8. The viscosity of the carbon/water nanofluid is dependent on the shear rate over the entire measured temperature range. The addition of as little as 0.02 wt.% (NC-70) or 0.04 wt.% (NC-80) carbon nanoparticles to the distilled water results in carbon/water nanofluid displaying non-Newtonian behavior (shear thinning). Carbon/water nanofluids display Newtonian behavior with higher shear rate (SR>350 s-1), but the temperature of NC-80 is greater than 40°C. Additionally, the rheological properties of carbon/water nanofluid approach Newtonian behavior and increase carbon/water nanofluid concentrations at low temperatures. This trend occurs because viscosity reduces as water temperatures increase, so the added nanoparticles will increase the fluid internal shear stresses that results to the observed nanofluid viscosity. Adding more nanoparticles would produce a similar effect. Figure 9 shows the change in viscosity ratio for carbon/water nanofluids compared to distilled water at various temperatures and under different process parameters. In general, nanofluid viscosity increases with increasing nanoparticle loading in the bulk liquid. For an NC-70 concentration of 0.02 wt.% and within a temperature range of 20-50°C, the viscosity ratio increases by 7.77-15.17%. For an NC-80 concentration of 0.04 wt.%, the viscosity ratio increases by 15.76-31.63%. In addition, Figure 9 shows the calculated results of Einstein's model [33] (Eq. 8) in comparison with the experimental results that show a serious underestimation, which may be results from the material properties and aggregation of carbon nanoparticles [34]. From the above results, it can be found that the viscosity of carbon/water nanofluid is much higher than that of the water. When the carbon/water nanofluid was applied to heat exchange, pressure drop of pipeline and energy consumption of pump-related issues must be considered in particular in the future.(8)

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