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Preparation and properties of copper-oil-based nanofluids.

Li D, Xie W, Fang W - Nanoscale Res Lett (2011)

Bottom Line: The effects of adding Cu nanoparticles on the thermal oxidation stability of the fluids were investigated by measuring the hydroperoxide concentration in the Cu/kerosene nanofluids.The hydroperoxide concentrations are observed to be clearly lower in the Cu nanofluids than in their base fluids.Appropriate amounts of metal nanoparticles added in a hydrocarbon fuel can enhance the thermal oxidation stability.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry and Chemical Engineering, Weifang University, Weifang 261061, China. danli830109@163.com.

ABSTRACT
In this study, the lipophilic Cu nanoparticles were synthesized by surface modification method to improve their dispersion stability in hydrophobic organic media. The oil-based nanofluids were prepared with the lipophilic Cu nanoparticles. The transport properties, viscosity, and thermal conductivity of the nanofluids have been measured. The viscosities and thermal conductivities of the nanofluids with the surface-modified nanoparticles have higher values than the base fluids do. The composition has more significant effects on the thermal conductivity than on the viscosity. It is valuable to prepare an appropriate oil-based nanofluid for enhancing the heat-transfer capacity of a hydrophobic system. The effects of adding Cu nanoparticles on the thermal oxidation stability of the fluids were investigated by measuring the hydroperoxide concentration in the Cu/kerosene nanofluids. The hydroperoxide concentrations are observed to be clearly lower in the Cu nanofluids than in their base fluids. Appropriate amounts of metal nanoparticles added in a hydrocarbon fuel can enhance the thermal oxidation stability.

No MeSH data available.


The change of hydroperoxide concentration in the nanofluid oxidized at 120°C and 140°C.
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Figure 7: The change of hydroperoxide concentration in the nanofluid oxidized at 120°C and 140°C.

Mentions: The hydroperoxides are the intermediates in the autoxidation reactions of hydrocarbon fuels. The hydroperoxide concentration is important for characterizing the thermal oxidation of a kerosene. Figure 7 gives the hydroperoxide concentration as a function of time in Cu/kerosene-based nanofluids and in kerosene without Cu nanoparticles thermal-oxidized at 120 and 140°C. As shown in Figure 7, the change of hydroperoxide concentration in the nanofluid oxidized at 120°C is nearly the same as that of the blank kerosene. At 140°C, the hydroperoxide concentrations in the nanofluid measured within 3 h are very low. It is clear that the hydroperoxide concentrations in the nanofluids are much lower than those in the blank kerosene during the thermal oxidation process. The Cu nanoparticles can significantly reduce the formation of the hydroperoxides in the kerosene. During the thermal oxidation at 140°C, the Cu nanoparticles deposit and react with oxygen. Therefore, the black CuO were found in the bottom of reactor. It indicated that the Cu nanoparticles were oxidized before the kerosene was oxidized. At lower temperatures, the coating layers on the surfaces of the nanoparticles prevent the Cu cores from oxidation. At higher temperatures, however, the coatings open or release from the surfaces, giving the opportunity for oxygen molecules to gain access to the Cu cores. The Cu nanoparticles then react with the oxygen before the kerosene is oxidized [19]. As a result, the hydroperoxide concentrations are observed to be relatively low in the Cu nanofluids. Appropriate amounts of metal nanoparticles added into a hydrocarbon fuel can enhance its thermal oxidation stability.


Preparation and properties of copper-oil-based nanofluids.

Li D, Xie W, Fang W - Nanoscale Res Lett (2011)

The change of hydroperoxide concentration in the nanofluid oxidized at 120°C and 140°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211464&req=5

Figure 7: The change of hydroperoxide concentration in the nanofluid oxidized at 120°C and 140°C.
Mentions: The hydroperoxides are the intermediates in the autoxidation reactions of hydrocarbon fuels. The hydroperoxide concentration is important for characterizing the thermal oxidation of a kerosene. Figure 7 gives the hydroperoxide concentration as a function of time in Cu/kerosene-based nanofluids and in kerosene without Cu nanoparticles thermal-oxidized at 120 and 140°C. As shown in Figure 7, the change of hydroperoxide concentration in the nanofluid oxidized at 120°C is nearly the same as that of the blank kerosene. At 140°C, the hydroperoxide concentrations in the nanofluid measured within 3 h are very low. It is clear that the hydroperoxide concentrations in the nanofluids are much lower than those in the blank kerosene during the thermal oxidation process. The Cu nanoparticles can significantly reduce the formation of the hydroperoxides in the kerosene. During the thermal oxidation at 140°C, the Cu nanoparticles deposit and react with oxygen. Therefore, the black CuO were found in the bottom of reactor. It indicated that the Cu nanoparticles were oxidized before the kerosene was oxidized. At lower temperatures, the coating layers on the surfaces of the nanoparticles prevent the Cu cores from oxidation. At higher temperatures, however, the coatings open or release from the surfaces, giving the opportunity for oxygen molecules to gain access to the Cu cores. The Cu nanoparticles then react with the oxygen before the kerosene is oxidized [19]. As a result, the hydroperoxide concentrations are observed to be relatively low in the Cu nanofluids. Appropriate amounts of metal nanoparticles added into a hydrocarbon fuel can enhance its thermal oxidation stability.

Bottom Line: The effects of adding Cu nanoparticles on the thermal oxidation stability of the fluids were investigated by measuring the hydroperoxide concentration in the Cu/kerosene nanofluids.The hydroperoxide concentrations are observed to be clearly lower in the Cu nanofluids than in their base fluids.Appropriate amounts of metal nanoparticles added in a hydrocarbon fuel can enhance the thermal oxidation stability.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry and Chemical Engineering, Weifang University, Weifang 261061, China. danli830109@163.com.

ABSTRACT
In this study, the lipophilic Cu nanoparticles were synthesized by surface modification method to improve their dispersion stability in hydrophobic organic media. The oil-based nanofluids were prepared with the lipophilic Cu nanoparticles. The transport properties, viscosity, and thermal conductivity of the nanofluids have been measured. The viscosities and thermal conductivities of the nanofluids with the surface-modified nanoparticles have higher values than the base fluids do. The composition has more significant effects on the thermal conductivity than on the viscosity. It is valuable to prepare an appropriate oil-based nanofluid for enhancing the heat-transfer capacity of a hydrophobic system. The effects of adding Cu nanoparticles on the thermal oxidation stability of the fluids were investigated by measuring the hydroperoxide concentration in the Cu/kerosene nanofluids. The hydroperoxide concentrations are observed to be clearly lower in the Cu nanofluids than in their base fluids. Appropriate amounts of metal nanoparticles added in a hydrocarbon fuel can enhance the thermal oxidation stability.

No MeSH data available.