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Particle shape effect on heat transfer performance in an oscillating heat pipe.

Ji Y, Wilson C, Chen HH, Ma H - Nanoscale Res Lett (2011)

Bottom Line: A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP.Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction.In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA. mah@missouri.edu.

ABSTRACT
The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP.

No MeSH data available.


Related in: MedlinePlus

TEM images of alumina nanoparticles (TEM images and designations provided by manufacturer) and photos of alumina nanofluids.
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Figure 2: TEM images of alumina nanoparticles (TEM images and designations provided by manufacturer) and photos of alumina nanofluids.

Mentions: For the current investigation, the nanoparticles of boehmite alumina with different shapes (platelet, blade, cylinder, and brick) were used. As shown in Figure 2, transmission electron microscopy (TEM: transmission electron microscopy) images were provided by the manufacturer (Sasol North America Inc.: Houston, Texas, U.S.) to determine the particle shape and size. EG 99+% (Fisher) and deionized water was mixed 50/50 by volume, and was used as the base fluid for all preparations. The particles were directly added into the base fluid at concentrations of 0.3, 1, 3, and 5 vol.%. As soon as the particles were added into the base fluid, the base fluid with particles was continuously mixed using a magnetic stirrer for 3 days. It was also sonicated with the ultrasonic oscillator for three 1-h sessions. Almost no sediments was observed a week after nanofluids preparation. Timofeeva et al. [17] studied the same nanofluids. The process of the nanofluids preparation was almost the same with the current investigation except that minor sediments were decanted a week after the nanofluid preparation in their work (maximum concentration change of 0.2 vol.%). The same nanoparticles and nanofluids were characterized carefully in [17] and the results showed that the crystallite sizes are close to particles size quoted by manufacturer, the alumina nanoparticles are composed of the same phase and mostly are single crystallites.


Particle shape effect on heat transfer performance in an oscillating heat pipe.

Ji Y, Wilson C, Chen HH, Ma H - Nanoscale Res Lett (2011)

TEM images of alumina nanoparticles (TEM images and designations provided by manufacturer) and photos of alumina nanofluids.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211362&req=5

Figure 2: TEM images of alumina nanoparticles (TEM images and designations provided by manufacturer) and photos of alumina nanofluids.
Mentions: For the current investigation, the nanoparticles of boehmite alumina with different shapes (platelet, blade, cylinder, and brick) were used. As shown in Figure 2, transmission electron microscopy (TEM: transmission electron microscopy) images were provided by the manufacturer (Sasol North America Inc.: Houston, Texas, U.S.) to determine the particle shape and size. EG 99+% (Fisher) and deionized water was mixed 50/50 by volume, and was used as the base fluid for all preparations. The particles were directly added into the base fluid at concentrations of 0.3, 1, 3, and 5 vol.%. As soon as the particles were added into the base fluid, the base fluid with particles was continuously mixed using a magnetic stirrer for 3 days. It was also sonicated with the ultrasonic oscillator for three 1-h sessions. Almost no sediments was observed a week after nanofluids preparation. Timofeeva et al. [17] studied the same nanofluids. The process of the nanofluids preparation was almost the same with the current investigation except that minor sediments were decanted a week after the nanofluid preparation in their work (maximum concentration change of 0.2 vol.%). The same nanoparticles and nanofluids were characterized carefully in [17] and the results showed that the crystallite sizes are close to particles size quoted by manufacturer, the alumina nanoparticles are composed of the same phase and mostly are single crystallites.

Bottom Line: A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP.Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction.In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA. mah@missouri.edu.

ABSTRACT
The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP.

No MeSH data available.


Related in: MedlinePlus