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Viscosity affected by nanoparticle aggregation in Al2O3-water nanofluids.

Duan F, Kwek D, Crivoi A - Nanoscale Res Lett (2011)

Bottom Line: The shear stress was observed with a non-Newtonian behavior.On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids.The microstructure analysis indicates that a higher nanoparticle aggregation had been observed in the nanofluids before re-ultrasonication.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore. feiduan@ntu.edu.sg.

ABSTRACT
An investigation on viscosity was conducted 2 weeks after the Al2O3-water nanofluids having dispersants were prepared at the volume concentration of 1-5%. The shear stress was observed with a non-Newtonian behavior. On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids. The relative viscosity increases as the volume concentrations increases. At 5% volume concentration, an increment was about 60% in the re-ultrasonication nanofluids in comparison with the base fluid. The microstructure analysis indicates that a higher nanoparticle aggregation had been observed in the nanofluids before re-ultrasonication.

No MeSH data available.


Related in: MedlinePlus

SEM microstructure of the dried Al2O3-water nanofluids before re-ultrasonication (a) and after re-ultrasonication (b).
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Figure 5: SEM microstructure of the dried Al2O3-water nanofluids before re-ultrasonication (a) and after re-ultrasonication (b).

Mentions: As illustrated in Figure 5, the microstructure of the nanoparticle distribution was measured after sampling and drying the drops at 5 vol% nanofluids which were held for 2 weeks and after re-ultrasonication. The nanoparticles accumulated together in a micron scale before re-ultrasonication of the 2-week nanofluids as seen in Figure 5a, while the slight aggregation of nanoparticles was well dispersed after re-ultrasonication as seen in Figure 5b.


Viscosity affected by nanoparticle aggregation in Al2O3-water nanofluids.

Duan F, Kwek D, Crivoi A - Nanoscale Res Lett (2011)

SEM microstructure of the dried Al2O3-water nanofluids before re-ultrasonication (a) and after re-ultrasonication (b).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211309&req=5

Figure 5: SEM microstructure of the dried Al2O3-water nanofluids before re-ultrasonication (a) and after re-ultrasonication (b).
Mentions: As illustrated in Figure 5, the microstructure of the nanoparticle distribution was measured after sampling and drying the drops at 5 vol% nanofluids which were held for 2 weeks and after re-ultrasonication. The nanoparticles accumulated together in a micron scale before re-ultrasonication of the 2-week nanofluids as seen in Figure 5a, while the slight aggregation of nanoparticles was well dispersed after re-ultrasonication as seen in Figure 5b.

Bottom Line: The shear stress was observed with a non-Newtonian behavior.On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids.The microstructure analysis indicates that a higher nanoparticle aggregation had been observed in the nanofluids before re-ultrasonication.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore. feiduan@ntu.edu.sg.

ABSTRACT
An investigation on viscosity was conducted 2 weeks after the Al2O3-water nanofluids having dispersants were prepared at the volume concentration of 1-5%. The shear stress was observed with a non-Newtonian behavior. On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids. The relative viscosity increases as the volume concentrations increases. At 5% volume concentration, an increment was about 60% in the re-ultrasonication nanofluids in comparison with the base fluid. The microstructure analysis indicates that a higher nanoparticle aggregation had been observed in the nanofluids before re-ultrasonication.

No MeSH data available.


Related in: MedlinePlus