陳瑤明臺灣大學：機械工程學研究所林修緯Lin, Hsiu-WeiHsiu-WeiLin2007-11-282018-06-282007-11-282018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/61011迴路式熱管是一種利用相變化散熱的散熱元件，擁有熱傳輸距離長、熱阻小、熱傳量大等優勢，為了應用於電子產品散熱，必須將迴路式熱管小型化，並藉由高性能的毛細結構來提升熱傳性能。故本實驗將研究迴路式熱管的主要元件-毛細結構，其中雙孔徑毛細結構是相當有研究價值的一項，而其同時擁有大孔徑以及小孔徑的孔徑分佈，將可提升熱傳性能。 本實驗中利用添加孔洞成型劑的方式來製造雙孔徑毛細結構，並控制孔洞成型劑的粒徑(改變大孔孔徑)、添加量(改變大小孔含量比例)以及燒結溫度(改變小孔孔徑)，以調控雙孔徑毛細結構的孔徑分佈，並以2-Level實驗設計進行，結果顯示當孔洞成型劑粉末粒徑較小、含量較多並且燒結溫度較高時，擁有較佳的熱傳性能，其中孔洞成型劑的含量為影響熱傳性能的關鍵。 成功製造出雙孔徑毛細結構，孔洞成型劑添加量30%、孔洞成型劑粉末粒徑為74~88μm、燒結溫度為750℃，其滲透度為1.034×10-11m2，孔隙度為83.1%，將其置入迴路式熱管進行熱傳性能測試，在熱沉10℃時，單孔徑毛細結構熱傳量為100W，熱阻為0.553 ℃/W，而雙孔徑毛細結構熱傳量可達400W以上，熱阻為0.297℃/W。Loop heat pipe (LHP) which is one of the phase-changing cooling devices could achieve long transport distance, low thermal resistance and high heat transfer. Recently, LHP was miniaturized and its performance was enhanced by improved the wick structure for electronic cooling. The main purpose of this study is to enhance the performance of miniature LHPs by using the bi-porous wick structures, which incorporates the advantages of different pore size distributions. In the experiments, nickel powders were mixed with the pore former (Na2CO3) to generate the bi-porous wick. To control the pore size distributions, the amount and particle size of pore formers, and the sintering temperature were investigated. Moreover, a two-level experiment-design was made to determine the optimized parameter combination of the bi-porous wick. The results showed that, smaller size and larger amount pore former, and higher sintering temperature would lead to better performance of the bi-porous wick. Among the various parameters, the amount of pore former is the key factor. The wick parameters of manufactured bi-porous wick, with the pore former content of 40%, the particle size of pore former of 74~88μm and the sintering temperature of 750℃ was measured. The permeability and porosity were found to be 1.034×10-11m2 and 83.1% respectively. The performance test under the heat sink temperature of 10℃ revealed that the heat transfer capacity of mono-porous LHP system was 100W and the thermal resistance was 0.553℃/W, While the bi-porous LHP achieved the maximum heat transport capability of 400W, and the thermal resistance was 0.297℃/W.第一章 緒論...................................1 1.1前言........................................1 1.2文獻回顧....................................4 1.3研究目的....................................7 第二章 實驗原理及理論分析......................8 2.1迴路式熱管操作原理..........................8 2.1.1毛細限制(Capillary Limitation)...........10 2.1.2啟動限制(Start-Up Limitation)............10 2.1.3液體過冷限(Liquid Subcooling Limitation).11 2.2壓降理論分析...............................12 2.2.1 液─汽界面之毛細壓差....................12 2.2.2 蒸發器溝槽內蒸汽流動壓降................13 2.2.3 汽體段流動壓降..........................14 2.2.4 毛細結構之壓降..........................15 2.2.5 液體段及冷凝段流動壓降..................16 2.2.6 重力壓降................................16 2.3毛細結構的作用.............................17 第三章 毛細結構的設計與製作.................19 3.1雙孔徑毛細結構原料與製造設備...............19 3.1.1實驗材料.................................19 3.1.2製造設備.................................20 3.2毛細結構的主要參數.........................22 3.2.1有效孔徑.................................22 3.2.2滲透度...................................23 3.2.3孔隙度...................................25 3.3雙孔徑毛細結構製作步驟.....................26 3.3.1製造步驟.................................26 3.3.2原料之選擇...............................29 3.3.3孔洞成形劑之選擇.........................30 3.3.4 混合方式................................31 3.4實驗設計...................................32 第四章 迴路式熱管實驗設備與測試步驟...........38 4.1熱傳性能測試設備...........................38 4.2 實驗方法..................................41 4.2.1迴路式熱管之安裝步驟.....................41 4.2.2熱傳性能測試步驟.........................42 4.3誤差分析...................................43 4.4實驗參數...................................46 第五章 結果與討論.............................47 5.1冷態性能測試...............................47 5.1.1有效孔徑分析.............................48 5.1.2孔隙度分析...............................50 5.1.3滲透度分析...............................51 5.2熱態性能測試...............................53 5.2.1各項變數對雙孔徑毛細結構的熱傳性能影響...53 5.2.2雙孔徑毛細結構之比較.....................56 5.2.3單孔徑與雙孔徑毛細結構之熱傳性能.........58 第六章 結論...................................62 6.1結論.......................................62 6.2建議.......................................63 參考文獻......................................64 附錄..........................................672375654 bytesapplication/pdfen-US迴路式熱管雙孔徑毛細結構孔徑分佈loop heat pipebiporous wick structurepore distributionthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/61011/1/ntu-95-R93522315-1.pdf