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Al2O3-based nanofluids: a review.

Sridhara V, Satapathy LN - Nanoscale Res Lett (2011)

Bottom Line: These suspended nanoparticles can change the transport and thermal properties of the base fluid.As can be seen from the literature, extensive research has been carried out in alumina-water and CuO-water systems besides few reports in Cu-water-, TiO2-, zirconia-, diamond-, SiC-, Fe3O4-, Ag-, Au-, and CNT-based systems.The Al2O3 nanoparticles varied in the range of 13 to 302 nm to prepare nanofluids, and the observed enhancement in the thermal conductivity is 2% to 36%.

View Article: PubMed Central - HTML - PubMed

Affiliation: Ceramic Technological Institute, BHEL, Malleswaram Complex, Bangalore 560012, India. satpathy@bhelepd.com.

ABSTRACT
Ultrahigh performance cooling is one of the important needs of many industries. However, low thermal conductivity is a primary limitation in developing energy-efficient heat transfer fluids that are required for cooling purposes. Nanofluids are engineered by suspending nanoparticles with average sizes below 100 nm in heat transfer fluids such as water, oil, diesel, ethylene glycol, etc. Innovative heat transfer fluids are produced by suspending metallic or nonmetallic nanometer-sized solid particles. Experiments have shown that nanofluids have substantial higher thermal conductivities compared to the base fluids. These suspended nanoparticles can change the transport and thermal properties of the base fluid. As can be seen from the literature, extensive research has been carried out in alumina-water and CuO-water systems besides few reports in Cu-water-, TiO2-, zirconia-, diamond-, SiC-, Fe3O4-, Ag-, Au-, and CNT-based systems. The aim of this review is to summarize recent developments in research on the stability of nanofluids, enhancement of thermal conductivities, viscosity, and heat transfer characteristics of alumina (Al2O3)-based nanofluids. The Al2O3 nanoparticles varied in the range of 13 to 302 nm to prepare nanofluids, and the observed enhancement in the thermal conductivity is 2% to 36%.

No MeSH data available.


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Thermal conductivity of Al2O3 nanofluids measured by different techniques. Steady-state parallel plate [8]; transient hot-wire method [1]; temperature oscillation technique [7]; 3ω method [23].
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Figure 8: Thermal conductivity of Al2O3 nanofluids measured by different techniques. Steady-state parallel plate [8]; transient hot-wire method [1]; temperature oscillation technique [7]; 3ω method [23].

Mentions: Figure 8 shows the thermal conductivity measurement of Al2O3 water-based nanofluid measured by different techniques. A trend shows that thermal conductivity increased with the increase in volume fraction. The thermal conductivity data in the case of Oh et al. [23] were in well agreement with that reported by Wang et al. [8] which, however, was higher than the results of Lee et al. [1] and Das et al. [7] for similar nanofluids but measured by different techniques. The reason for this discrepancy during the measurement may be due to the sedimentation and aggregation of nanoparticles, particle diameter, and nanofluid preparation. In comparing the thermal conductivity measurement techniques, the steady state parallel plate method seems to be least affected by the particle sedimentation since the thickness of the loaded sample fluid is less than 1 mm. The transient hot-wire method can be affected by the sedimentation of the nanofluids. Non-homogeneous nanoparticle concentration in the direction of gravity can give rise to temperature gradient within the vertical hot wire, which may be a source of measurement errors. This is also true for the temperature oscillation technique [23]. It is not clear how these techniques will behave for a stable nanofluid which does not at all sediment during the measurement. Therefore, it is essential to produce nanofluids which can be stable for long periods of time without any noticeable sedimentation.


Al2O3-based nanofluids: a review.

Sridhara V, Satapathy LN - Nanoscale Res Lett (2011)

Thermal conductivity of Al2O3 nanofluids measured by different techniques. Steady-state parallel plate [8]; transient hot-wire method [1]; temperature oscillation technique [7]; 3ω method [23].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211876&req=5

Figure 8: Thermal conductivity of Al2O3 nanofluids measured by different techniques. Steady-state parallel plate [8]; transient hot-wire method [1]; temperature oscillation technique [7]; 3ω method [23].
Mentions: Figure 8 shows the thermal conductivity measurement of Al2O3 water-based nanofluid measured by different techniques. A trend shows that thermal conductivity increased with the increase in volume fraction. The thermal conductivity data in the case of Oh et al. [23] were in well agreement with that reported by Wang et al. [8] which, however, was higher than the results of Lee et al. [1] and Das et al. [7] for similar nanofluids but measured by different techniques. The reason for this discrepancy during the measurement may be due to the sedimentation and aggregation of nanoparticles, particle diameter, and nanofluid preparation. In comparing the thermal conductivity measurement techniques, the steady state parallel plate method seems to be least affected by the particle sedimentation since the thickness of the loaded sample fluid is less than 1 mm. The transient hot-wire method can be affected by the sedimentation of the nanofluids. Non-homogeneous nanoparticle concentration in the direction of gravity can give rise to temperature gradient within the vertical hot wire, which may be a source of measurement errors. This is also true for the temperature oscillation technique [23]. It is not clear how these techniques will behave for a stable nanofluid which does not at all sediment during the measurement. Therefore, it is essential to produce nanofluids which can be stable for long periods of time without any noticeable sedimentation.

Bottom Line: These suspended nanoparticles can change the transport and thermal properties of the base fluid.As can be seen from the literature, extensive research has been carried out in alumina-water and CuO-water systems besides few reports in Cu-water-, TiO2-, zirconia-, diamond-, SiC-, Fe3O4-, Ag-, Au-, and CNT-based systems.The Al2O3 nanoparticles varied in the range of 13 to 302 nm to prepare nanofluids, and the observed enhancement in the thermal conductivity is 2% to 36%.

View Article: PubMed Central - HTML - PubMed

Affiliation: Ceramic Technological Institute, BHEL, Malleswaram Complex, Bangalore 560012, India. satpathy@bhelepd.com.

ABSTRACT
Ultrahigh performance cooling is one of the important needs of many industries. However, low thermal conductivity is a primary limitation in developing energy-efficient heat transfer fluids that are required for cooling purposes. Nanofluids are engineered by suspending nanoparticles with average sizes below 100 nm in heat transfer fluids such as water, oil, diesel, ethylene glycol, etc. Innovative heat transfer fluids are produced by suspending metallic or nonmetallic nanometer-sized solid particles. Experiments have shown that nanofluids have substantial higher thermal conductivities compared to the base fluids. These suspended nanoparticles can change the transport and thermal properties of the base fluid. As can be seen from the literature, extensive research has been carried out in alumina-water and CuO-water systems besides few reports in Cu-water-, TiO2-, zirconia-, diamond-, SiC-, Fe3O4-, Ag-, Au-, and CNT-based systems. The aim of this review is to summarize recent developments in research on the stability of nanofluids, enhancement of thermal conductivities, viscosity, and heat transfer characteristics of alumina (Al2O3)-based nanofluids. The Al2O3 nanoparticles varied in the range of 13 to 302 nm to prepare nanofluids, and the observed enhancement in the thermal conductivity is 2% to 36%.

No MeSH data available.


Related in: MedlinePlus