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Numerical evaluation of laminar heat transfer enhancement in nanofluid flow in coiled square tubes.

Sasmito AP, Kurnia JC, Mujumdar AS - Nanoscale Res Lett (2011)

Bottom Line: The two nanofluid suspensions examined in this study are: water-Al2O3 and water-CuO.The flow behavior and heat transfer performance of these nanofluid suspensions in various configurations of coiled square tubes, e.g., conical spiral, in-plane spiral, and helical spiral, are investigated and compared with those for water flowing in a straight tube.Laminar flow of a Newtonian nanofluid in coils made of square cross section tubes is simulated using computational fluid dynamics (CFD)approach, where the nanofluid properties are treated as functions of particle volumetric concentration and temperature.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576 Singapore. jc.kurnia@nus.edu.sg.

ABSTRACT
Convective heat transfer can be enhanced by changing flow geometry and/or by enhancing thermal conductivity of the fluid. This study proposes simultaneous passive heat transfer enhancement by combining the geometry effect utilizing nanofluids inflow in coils. The two nanofluid suspensions examined in this study are: water-Al2O3 and water-CuO. The flow behavior and heat transfer performance of these nanofluid suspensions in various configurations of coiled square tubes, e.g., conical spiral, in-plane spiral, and helical spiral, are investigated and compared with those for water flowing in a straight tube. Laminar flow of a Newtonian nanofluid in coils made of square cross section tubes is simulated using computational fluid dynamics (CFD)approach, where the nanofluid properties are treated as functions of particle volumetric concentration and temperature. The results indicate that addition of small amounts of nanoparticles up to 1% improves significantly the heat transfer performance; however, further addition tends to deteriorate heat transfer performance.

No MeSH data available.


Related in: MedlinePlus

(a) Mixed mean temperature and (b) total heat transfer of water and nanofliuds (Al2O3 and CuO) inside an in-plane coiled tube along the tube length.
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Figure 11: (a) Mixed mean temperature and (b) total heat transfer of water and nanofliuds (Al2O3 and CuO) inside an in-plane coiled tube along the tube length.

Mentions: The heat transfer performance of two different nanofluid types is further evaluated in terms of the local mixed mean temperature and total heat transfer. As seen in Figure 11, the mixed mean temperature for the nanofluid is around 15% higher than that of water. There is no discernible difference between Al2O3 and CuO suspensions in terms of the mixed mean temperature. For total heat transfer, Al2O3 gives somewhat higher heat transfer (approximately 5%) when compared to the CuO nanofluid. Therefore, it can be deduced that Al2O3 nanofluid performs better heat transfer performance than that of CuO nanofluid, but not significantly. The stability and cost would decide the selection between these two nanofluids.


Numerical evaluation of laminar heat transfer enhancement in nanofluid flow in coiled square tubes.

Sasmito AP, Kurnia JC, Mujumdar AS - Nanoscale Res Lett (2011)

(a) Mixed mean temperature and (b) total heat transfer of water and nanofliuds (Al2O3 and CuO) inside an in-plane coiled tube along the tube length.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211469&req=5

Figure 11: (a) Mixed mean temperature and (b) total heat transfer of water and nanofliuds (Al2O3 and CuO) inside an in-plane coiled tube along the tube length.
Mentions: The heat transfer performance of two different nanofluid types is further evaluated in terms of the local mixed mean temperature and total heat transfer. As seen in Figure 11, the mixed mean temperature for the nanofluid is around 15% higher than that of water. There is no discernible difference between Al2O3 and CuO suspensions in terms of the mixed mean temperature. For total heat transfer, Al2O3 gives somewhat higher heat transfer (approximately 5%) when compared to the CuO nanofluid. Therefore, it can be deduced that Al2O3 nanofluid performs better heat transfer performance than that of CuO nanofluid, but not significantly. The stability and cost would decide the selection between these two nanofluids.

Bottom Line: The two nanofluid suspensions examined in this study are: water-Al2O3 and water-CuO.The flow behavior and heat transfer performance of these nanofluid suspensions in various configurations of coiled square tubes, e.g., conical spiral, in-plane spiral, and helical spiral, are investigated and compared with those for water flowing in a straight tube.Laminar flow of a Newtonian nanofluid in coils made of square cross section tubes is simulated using computational fluid dynamics (CFD)approach, where the nanofluid properties are treated as functions of particle volumetric concentration and temperature.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576 Singapore. jc.kurnia@nus.edu.sg.

ABSTRACT
Convective heat transfer can be enhanced by changing flow geometry and/or by enhancing thermal conductivity of the fluid. This study proposes simultaneous passive heat transfer enhancement by combining the geometry effect utilizing nanofluids inflow in coils. The two nanofluid suspensions examined in this study are: water-Al2O3 and water-CuO. The flow behavior and heat transfer performance of these nanofluid suspensions in various configurations of coiled square tubes, e.g., conical spiral, in-plane spiral, and helical spiral, are investigated and compared with those for water flowing in a straight tube. Laminar flow of a Newtonian nanofluid in coils made of square cross section tubes is simulated using computational fluid dynamics (CFD)approach, where the nanofluid properties are treated as functions of particle volumetric concentration and temperature. The results indicate that addition of small amounts of nanoparticles up to 1% improves significantly the heat transfer performance; however, further addition tends to deteriorate heat transfer performance.

No MeSH data available.


Related in: MedlinePlus