氧化銅奈米流體熱性質分析與應用研究

The Thermal Property and Application of Copper Oxide Nanofluids

洪忠仁(Chung-Jen Hung)

指導教授 ： 卓清松

國立臺北科技大學/機電學院/冷凍空調工程系所/碩士(2005年)

https://doi.org/10.6841/NTUT.2005.00284

摘要

本研究使用以真空潛弧製造系統製備之氧化銅奈米流體為實驗樣本，首先分析其熱性質，做為應用研究基礎，探討添加氧化銅奈米顆粒在不同體積濃度與溫度條件下，針對其熱傳導係數與黏滯係數進行實驗分析。並將奈米流體實際應用於儲冷冰球，觀察其結冰與釋冷之狀況，評估應用於冰球儲冷系統的可行性。
由研究結果發現：在奈米流體體積濃度影響方面，樣本溫度40 ℃時，0.2 %vol能提升熱傳導係數5.1%，當體積濃度上升到0.8 %vol時，則能上升到22%，同樣條件之下，0.2 %vol能提升黏滯係數增加4%，當體積濃度上升到0.8 %vol時，則能上升到14%，體積濃度對於熱傳導係數及黏滯係數的增進率均呈現正比關係。在實驗樣本溫度影響方面，體積濃度0.8 %vol時，樣本5 ℃時能提升熱傳導係數2.5%，當溫度上升到40 ℃時，則能上升到23%，同樣條件之下，樣本5 ℃能提升黏滯係數增加4%，當溫度上升到40 ℃時，則能上升到14%。濃度與溫度對於熱傳導係數的影響均大於對黏滯度的影響。在儲能冰球應用研究方面，發現添加奈米顆粒能改善水的過冷現象，冷卻溫度越高則改善的效果越明顯，在冷卻溫度-6 ℃時，約能減低0.5 ℃的過冷度，在冷卻溫度到達-15 ℃時，過冷卻溫度的改善則不明顯。未來必須針對提高體積分率、不同材料與粒徑等方面進行相關的研究，以期將奈米流體的相關應用能更貼近實務面。

關鍵字

氧化銅 ； 奈米流體 ； 真空潛弧製造系統 ； 熱傳導係數 ； 黏滯係數

並列摘要

In this study, the samlpe of CuO nanofluids are prepared by the submerged arc nanoparticle synthesis system （SANSS）. Their thermal properties are first analyzed to be the research bases, and then it is experimented that the variation of the thermal conductivity and viscosity for fluids in different volume fraction of CuO nanoparticles and different temperature. Finally, these nanofluids are used in the ice capsules, and the practicability of being applied in thermal storage system will be estimated by surveying the freezing and melting condition.
From the experimental results, it is found as follows. At 40 ℃, for the effect of the volume fraction, the fluids of 0.2 %vol elevate thermal conductivity 5.1%, and those of 0.8 %vol elevate thermal conductivity 22%. Besides, at the same condition, the fluids of 0.2 %vol elevate viscosity 4%, and those of 0.8 %vol elevate viscosity 14%. The increment of the thermal conductivity and viscosity is about proportional to the volume fraction. At 0.8 %vol, for the effect of the temperature of the fluids, the fluids at 5 ℃ elevate thermal conductivity 2.5%, and those at 40 ℃ elevate thermal conductivity 23%. Besides, at the same condition, the fluids at 5 ℃ elevate viscosity 4%, and those at 40 ℃ elevate viscosity 14%. The effects of the volume fraction and temperature on the thermal conductivity are larger than those on the viscosity. For the application of ice capsules, it is found that adding nanoparticles can improve the supercooling problem and more for higher cooling temperature. At -6 ℃ of cooling temperature, the supercooling degree is reduced 0.5 ℃, but At -15 ℃ of cooling temperature, the supercooling degree is reduced very little. In the future, one studies on high volume fraction, different materials and different particle sizes to make nanofluids more practicable.

並列關鍵字

CuO ； nanofluids ； SANSS ； thermal conductivity ； viscosity

參考文獻

[6] 徐建力，奈米流體之熱傳效能分析，碩士，中原大學機械工程學系，桃園，2002。

[37] 陳智銘，連續式真空潛弧製造系統之研製，碩士，臺北科技大學製造科技研究所，臺北，2005。

[1] R. P. Fey nman, "There's Plenty of Room at the Bottom", annual meeting of the American Physical Society, December 29, 1959.

[7] J.A. Eastman, S.U.S. Choi, S. Li, L.J. Thompson, S. Lee, “Enhanced thermal conductivity through the development of nanofluid,” Nanophase and Nanocomposite Materials II.MRS, Pittsburg, PA, 1997, pp.3-11.

[8] S. Lee, S.U.S. Choi, S. Li, J.A. Eastman, ”Measuring thermal conductivity of oxide nanoparticles,”ASME J. Heat Transfer, vol.121, 1999, pp. 280-289.