微型毛細泵吸環路應用於LED散熱之研製與測試

Fabrication and Test for Micro-CPL applied on LED Heat Dissipation Device

黃朝揚(Chao-Yang Huang)

指導教授 ： 林唯耕

國立清華大學/原子科學院/工程與系統科學系/碩士(2008年)

摘要

近年來由於電晶體密度增加造成所產生的熱也隨之倍增，加上LED體積小造成局部溫度過高也成為散熱不易的主要原因。為了達到被動式運作，必須使流體能藉由自然毛細力來帶動整個系統循環，因此設計出微型毛細泵吸環路之蒸發區並能夠克服蒸汽回衝現象的結構；以及確保環路內真空度的要求是本研究的重點。
完成環路後在熱源測試實驗採用模擬LED點熱源加熱形式進行加熱測試，從蒸發部以及環路流況觀察發現蒸發部蒸氣能夠往出口端衝出並推動環路內流體流入蒸發部進行移熱作用，而流體的動作是週期性地填充進入蒸發部。
本實驗針對扣具壓力、不同冷凝度以及兩種蒸發部流道結構進行比較分析。扣具壓力與蒸發部及加熱同棒間的接觸熱阻有關，在固定輸入功率3W，環境溫度30度時，扣具壓力為1kg重時有CPU溫度84度；3kg重時CPU溫度為79度，熱阻值為16.3(℃/W)。不同冷凝度將會影響裝置移熱能力的表現，在冷凝度25度以上時，環路內液體的流動不明顯，且熱阻值為17.5(℃/W)；當冷凝度在10℃時則有最小熱阻值15.9(℃/W) 。由於蒸發部體積佔整個環路比例過小，故兩種蒸發部結構測試結果並無太大差異。

關鍵字

LED ； 毛細力 ； 微型毛細泵吸環路

並列摘要

In the recent years, complying with increase of the transistor density, heat generated from these electronic devices was usually grown doubly. Due to the reason of the tiny heat source area, the heat flux turn out to be very large and result in the difficulty of the heat dissipation.
The purpose of this study was trying to develop a micro-capillary-pumped-loop (μ-CPL) that could carry away 3W of the heat by means of the natural convection. From the observation of the transparent loop, one may found the vapor generated from evaporator was pushing out to the evaporator line and condensed to the liquid form at condenser section then back to the evaporator periodically. The experimental result was shown the contact resistant between evaporator and copper rod was related to the fixed pressure. For a typical case, at 3W heat input with surrounding temperature 30℃, the CPU temperature was 79℃ and the thermal resistant was 16.3(℃/W) as fixed pressure in 3kg. The micro CPL was cooed by a water jacket, therefore the cooling water temperature affected the thermal resistance of the CPL as well. When the cooling water temperature was above 25℃, the thermal resistant was 17.5(℃/W) and the fluid flow in the loop was not apparent. When the cooling water temperature was down to 10℃, the thermal resistant was 15.9(℃/W). There were two different evaporator structures, parallel and nozzle. Test results showed the performance of these two structures weren’t different too much in this study.

並列關鍵字

LED ； Capillary force ； Micro Capillary pumped Loop

參考文獻

2. Kirshberg, J., Yerkes, K., and Liepmann, D., 1999 “Micro-Cooler for Chip-Level Temperature Control,” SAE Aerospace Power Systems Conference, P-341.

3. Jeffrey Kirshberg, Kirk Yerkes, Dorian Liepmann and David Trebotich” Cooling effect of a MEMS based micro capillary pumped loop for chip-lever temperature control”,ASME,2000.

5. L. Meyer, S. Dasgupta, D. Shaddock, J. Tucker, R. Fillion, P. Bronecke,L. Yorinks, and P. Kraft”A Silicon-Carbide Micro-Capillary Pumped Loopfor Cooling High Power Devices ”,IEEE,2003.

7. Chin-Tsan Wang, Tzong-Shyng Leu, Tsai-Ming Lai, “Micro Capillary Pumped Loop System for a Cooling High Power Device”, Experimental Thermal and Fluid Science 32 (2008) 1090–1095

8. Dickey, J.T. , and Peterson G.P. , 1994,”Experimental and Analytical Investigation of a Capillary Pumped Loop,”Journal of Thermophysics and Heat Transfer, Vol 8, No. 3, pp. 602-607.