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Investigation on two abnormal phenomena about thermal conductivity enhancement of BN/EG nanofluids.

Li Y, Zhou J, Luo Z, Tung S, Schneider E, Wu J, Li X - Nanoscale Res Lett (2011)

Bottom Line: The thermal conductivity of boron nitride/ethylene glycol (BN/EG) nanofluids was investigated by transient hot-wire method and two abnormal phenomena was reported.The chain-like loose aggregation of nanoparticles is responsible for the abnormal increment of thermal conductivity enhancement for the BN/EG nanofluids at very low particles volume fraction.And the difference in specific surface area and aspect ratio of BN nanoparticles may be the main reasons for the abnormal difference between thermal conductivity enhancements for BN/EG nanofluids prepared with 140- and 70-nm BN nanoparticles, respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, Shanxi, 710049, China. lyj.xjtu@yahoo.com.cn.

ABSTRACT
The thermal conductivity of boron nitride/ethylene glycol (BN/EG) nanofluids was investigated by transient hot-wire method and two abnormal phenomena was reported. One is the abnormal higher thermal conductivity enhancement for BN/EG nanofluids at very low-volume fraction of particles, and the other is the thermal conductivity enhancement of BN/EG nanofluids synthesized with large BN nanoparticles (140 nm) which is higher than that synthesized with small BN nanoparticles (70 nm). The chain-like loose aggregation of nanoparticles is responsible for the abnormal increment of thermal conductivity enhancement for the BN/EG nanofluids at very low particles volume fraction. And the difference in specific surface area and aspect ratio of BN nanoparticles may be the main reasons for the abnormal difference between thermal conductivity enhancements for BN/EG nanofluids prepared with 140- and 70-nm BN nanoparticles, respectively.

No MeSH data available.


Comparison of experimental results and theoretical model on thermal conductivity enhancement of BN/EG nanofluids vs. volume fraction of BN nanoparticles.
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Figure 2: Comparison of experimental results and theoretical model on thermal conductivity enhancement of BN/EG nanofluids vs. volume fraction of BN nanoparticles.

Mentions: Figure 2 shows the thermal conductivity enhancement of BN/EG nanofluids as a function of particle volume fraction. For volume fraction varying from 0.2 vol.% to 5.5 vol.%, data fitting indicates that the thermal conductivity enhancement of BN/EG nanofluids increases linearly with the increment of nanoparticle volume fraction. The R value is 0.9981. The thermal conductivity enhancement predicted by Maxwell's model [44] and Nan's model [27] were also illustrated in Figure 2. Based on Maxwell's work, the effective thermal conductivity of a homogeneous suspension can be predicted as (Maxwell, 1873)(1)


Investigation on two abnormal phenomena about thermal conductivity enhancement of BN/EG nanofluids.

Li Y, Zhou J, Luo Z, Tung S, Schneider E, Wu J, Li X - Nanoscale Res Lett (2011)

Comparison of experimental results and theoretical model on thermal conductivity enhancement of BN/EG nanofluids vs. volume fraction of BN nanoparticles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211862&req=5

Figure 2: Comparison of experimental results and theoretical model on thermal conductivity enhancement of BN/EG nanofluids vs. volume fraction of BN nanoparticles.
Mentions: Figure 2 shows the thermal conductivity enhancement of BN/EG nanofluids as a function of particle volume fraction. For volume fraction varying from 0.2 vol.% to 5.5 vol.%, data fitting indicates that the thermal conductivity enhancement of BN/EG nanofluids increases linearly with the increment of nanoparticle volume fraction. The R value is 0.9981. The thermal conductivity enhancement predicted by Maxwell's model [44] and Nan's model [27] were also illustrated in Figure 2. Based on Maxwell's work, the effective thermal conductivity of a homogeneous suspension can be predicted as (Maxwell, 1873)(1)

Bottom Line: The thermal conductivity of boron nitride/ethylene glycol (BN/EG) nanofluids was investigated by transient hot-wire method and two abnormal phenomena was reported.The chain-like loose aggregation of nanoparticles is responsible for the abnormal increment of thermal conductivity enhancement for the BN/EG nanofluids at very low particles volume fraction.And the difference in specific surface area and aspect ratio of BN nanoparticles may be the main reasons for the abnormal difference between thermal conductivity enhancements for BN/EG nanofluids prepared with 140- and 70-nm BN nanoparticles, respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, Shanxi, 710049, China. lyj.xjtu@yahoo.com.cn.

ABSTRACT
The thermal conductivity of boron nitride/ethylene glycol (BN/EG) nanofluids was investigated by transient hot-wire method and two abnormal phenomena was reported. One is the abnormal higher thermal conductivity enhancement for BN/EG nanofluids at very low-volume fraction of particles, and the other is the thermal conductivity enhancement of BN/EG nanofluids synthesized with large BN nanoparticles (140 nm) which is higher than that synthesized with small BN nanoparticles (70 nm). The chain-like loose aggregation of nanoparticles is responsible for the abnormal increment of thermal conductivity enhancement for the BN/EG nanofluids at very low particles volume fraction. And the difference in specific surface area and aspect ratio of BN nanoparticles may be the main reasons for the abnormal difference between thermal conductivity enhancements for BN/EG nanofluids prepared with 140- and 70-nm BN nanoparticles, respectively.

No MeSH data available.