三氧化二鋁奈米流體應用於電子散熱之效益研究

A Study the Performance of Al2O3 Nanofluids Applied to Electronic Cooling

陳廷昱(Ting-Yu Chen)

指導教授 ： 卓清松

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2010年)

摘要

本文主要探討奈米流體的基礎性質特性及評估應用於電子散熱系統的可行性。研究中所使用的奈米粉末為商用15nm三氧化二鋁，採用二階混合法製備成奈米流體。以實驗研究的方式進行探討在不同分散劑、濃度與溫度下對奈米流體基本性質的影響，同時透過實際應用於伺服器電腦中，藉此測試CPU的散熱效益以及評估奈米流體散熱系統的效能。實驗結果顯示：添加0.05wt.%陽離子分散劑且濃度為1.0wt.%三氧化二鋁粉末的奈米流體比未添加分散劑之表面電位增進24%，可減少奈米顆粒團聚的現象產生。在溫度40℃、熱功率150W時，總熱傳係數雖然較無添加分散劑之1.0wt.%三氧化二鋁奈米流體降低0.9%的熱傳增進，但仍有17.4%增進率的表現。由模擬運轉的實驗結果得知添加陽離子分散劑能夠減少奈米顆粒附著於管壁的情形發生。此外，在伺服電腦散熱裝置實驗中，使用添加分散劑奈米流體之水冷式散熱系統比氣冷式散熱系統、水冷式(去離子水)散熱系統之平均機內環境溫度分別降低14.8℃與0.5℃，CPU平均溫度分別降低19.2℃與1.2℃，此降低電腦系統之環境溫度與操作溫度將有效節省能源的消耗。
本研究主要針對三氧化二鋁奈米流體進行一系列相關基本性質與實機應用研究，主要貢獻在於添加分散劑對於奈米流體與實機應用的影響，研究證實添加陽離子分散劑能提升奈米顆粒的分散性與降低奈米顆粒於系統中附著於管壁的行為，並能有效提升奈米流體實際應用的可行性。

關鍵字

奈米流體 ； 電子散熱 ； 分散劑 ； 能源消耗

並列摘要

This paper mainly discusses the fundamental characters of nanofluids and evaluates the applicability of applying it to the cooling system of electronic device. The study uses the 15mm aluminum oxide (Al2O3 ) and two-step synthesis to prepare nanofluids. Using experimental research method, this paper investigates how different dispersants, concentration, and temperature conditions might affect the basic characters of nanofluids. This study also tests the CPU’s cooling efficiency and evaluates the efficiency of nanofluids cooling system through experiment with proxy computers. As the research results shows, the surface potential of Al2O3 nanofluids at concentration 1.0%wt., added with 0.05%wt cationic dispersant, increases by 24% than the same nanofluids without dispersant, and the nanoparticles aggregation phenomenon is less. Although under the conditions of 40℃, the thermal power of 150W, and the concentration 10%wt, the total thermal conductivity coefficient of Al2O3 nanofluids is less in thermal conductivity enhancement than the nanofluids without dispersant by 0.9%, still its enhancement rate is 17.4%. Through simulation, the results show that adding cationic dispersant could prevent nanoparticles from attaching to walls. Also, in proxy computer cooling device experiment, the average machine temperature of using water-cooled cooling system with dispersant added nanofluids is lower than the air-cooled cooling system and the deionized water-cooled cooling system by 14.8℃ and 0.5℃ respectively. The CPU average temperature is also lower by 19.2℃ and 1.2℃. The reduction of computer system’s environmental and operating temperature would save energy effectively. This research mainly focuses on Al2O3 nanofluids and conducted a series of researches on its relative basic characters and practical applications. The main contribution of this study is the effectiveness of dispersant adding to nanofluids and its practical application. The result shows that adding cationic dispersant could improve the dispersion of nanoparticles and reduce the possibility of nanoparticles attaching to walls, thus improve the feasibility of practical application of nanofluids.

並列關鍵字

nanofluids ； electric cooling ； dispersant ； energy consumption

參考文獻

[8] L. D. Chang and C. M. Mou, Nanomaterials and Nanostructure,Peking：Science Press,2001

[1] R. P. Feynman, “There's Plenty of Room at the Bottom”, Annual Meeting of The American Physical Society, Dec., 29, 1959.

[4] Semi-conductor Industry Association, International Technology Roadmap for Semiconductors, 2006 Update.

[5] 吳孟勳，微流道蒸氣壓縮循環電子散熱系統，碩士論文，國立臺灣大學機械工程學研究所，2008，第12頁。

[6] J. Kestin and W.A. Wakeham, “A contribution to the theory of the transient hot-wire technique for thermal conductivity measurements,” Physica A, 92, 1978, pp.102-116.