應用奈米流體於冷凍吸盤流道設計之研究

Implementation of Nanofluids for Channel Flow Design of a Freezing Chucker

李宜儒(I-Lu Lee)

國立虎尾科技大學/工程學院/動力機械工程研究所/碩士(2006年)

摘要

本研究之目的在於探討冷凍吸盤流道設計及其未來發展潛力，並以奈米銅金屬粉末混合於乙二醇(EG)冷卻液內，以提升流道結構之熱傳增強效果。經由文獻回顧及分析，本文提出三種不同流道形式，分別應用於冷凍吸盤之結構中，並以數值分析與實驗方法來探討三種流道設計之熱傳特性。本研究以實驗的方式探討不同流道在不同濃度的奈米流體中，其對冷凍吸盤穩態溫度分佈分析與冷凍/解凍時之暫態溫升/溫降速率之影響。相關參數範圍為：冷卻液溫度維持進口溫度Tin為258.15K、263.15K及 268.15K，流體流量為5 L/min、8 L/min及9 L/min，奈米流體體積百分濃度為0.1 vol % 及0.5 vol % 。本實驗並利用PHOENICS 3.3分析軟體，以數值分析方式獲得在各流道內流體之溫度、速度場及壓力及盤面溫度分佈，並與實驗模型加以比較驗證。由實驗與分析結果顯示，縱向直肋流道在不同進口溫度及流量下，其鈕塞數是較方型橫向肋流道與平滑壁流道
高，由分析結果顯示奈米流體體積百分濃度越高，在不同進口溫度及流量鈕塞數是更高。

並列摘要

The design and analysis of the channel flow of a freezing-chucker structure and its applicability in future applications are studied in this thesis. Nanoparticles of copper is mixed with base fluid of EG and this mixture is flowing inside the channel of a freezing-chucker to enhance its heat transfer capability. From comprehensive review for channel flow researches, three channel configurations are proposed and designed for the freezing-chucker. Moreover, numerical modeling and experimental measurements are conducted to explore the heat transfer characteristics. In experiments, measurements are conducted for three channel designs and for different concentrations of nanofluids and the steady-state temperature distributions of the freezing-chucker and the transient decaying/increasing rate of temperature during freezing/thawing operation states. Physical parameters studied in this thesis include: inlet temperatures of 258.15K, 263.15K and 268.15K, flow rates of 5L/min, 8L/min, and 9L/min, and nanofluid concentrations of 0.1vol% and 0.5vol%, respectively. Meanwhile, the PHOENICS 3.3 package is adopted to analyze the temperature, velocity, and pressure fields inside the channel flow and the surface temperature of the freezing-chucker. Analyses are compared to the experimental results. From the above investigations show, as to the channel with transverse square ribs, the nusselt Number for different inlet temperatures and different flow rates are higher than the smooth channel and the multi-walls channel cases. Also, volume
percentage of nanofluids is helpful to increase the Nusselt number.

參考文獻

[40] 徐健力,“奈米流體之熱傳效能分析,” 中原大學機械工程研究所碩士論文 (2002).

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