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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

Schematic of experimental system (units in mm).
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Figure 1: Schematic of experimental system (units in mm).

Mentions: The experimental system shown in Figure 1 consists of an OHP, circulator (Julabo-F34), cooling block, NI-DAQ system, power supply (Agilent-N5750A), and electrical flat heater. In order to form liquid plugs, a copper tube with an inner diameter of 1.65 mm and outer diameter of 3.18 mm was used for the OHP in the current investigation. As shown in Figure 1, the OHP has six turns and three sections: evaporator, condenser, and adiabatic section with the lengths of 40, 64, and 51 mm, respectively. The OHP was tested vertically, i.e., the evaporator on the bottom heated by a uniform electrical flat heater. The condenser section was directly attached to a cooling block which was cooled by a constant-temperature circulator. The data acquisition system controlled by a computer was used to record the experimental data. A total of 18 T-type thermocouples were placed on the outer surface of the OHP as shown in Figure 1 to measure the wall temperatures of the OHP. Figure 1 shows the locations of these thermocouples. The temperature measurement accuracy of the whole DAQ system is ± 0.25°C. The whole test section including the OHP, cooling block, and heater were well insulated to minimize the heat loss. Based on the insulation surface temperature, the power input uncertainty is less than 5% of the total power input.


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

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

Schematic of experimental system (units in mm).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Schematic of experimental system (units in mm).
Mentions: The experimental system shown in Figure 1 consists of an OHP, circulator (Julabo-F34), cooling block, NI-DAQ system, power supply (Agilent-N5750A), and electrical flat heater. In order to form liquid plugs, a copper tube with an inner diameter of 1.65 mm and outer diameter of 3.18 mm was used for the OHP in the current investigation. As shown in Figure 1, the OHP has six turns and three sections: evaporator, condenser, and adiabatic section with the lengths of 40, 64, and 51 mm, respectively. The OHP was tested vertically, i.e., the evaporator on the bottom heated by a uniform electrical flat heater. The condenser section was directly attached to a cooling block which was cooled by a constant-temperature circulator. The data acquisition system controlled by a computer was used to record the experimental data. A total of 18 T-type thermocouples were placed on the outer surface of the OHP as shown in Figure 1 to measure the wall temperatures of the OHP. Figure 1 shows the locations of these thermocouples. The temperature measurement accuracy of the whole DAQ system is ± 0.25°C. The whole test section including the OHP, cooling block, and heater were well insulated to minimize the heat loss. Based on the insulation surface temperature, the power input uncertainty is less than 5% of the total power input.

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