DC 欄位 | 值 | 語言 |
dc.contributor | 陳瑤明 | zh-TW |
dc.contributor | Chen, Yau-Ming | en |
dc.contributor | 臺灣大學:機械工程學研究所 | zh-TW |
dc.contributor.author | 黃祺庭 | zh-TW |
dc.contributor.author | Huang, Chi-Ting | en |
dc.creator | 黃祺庭 | zh-TW |
dc.creator | Huang, Chi-Ting | en |
dc.date | 2008 | en |
dc.date.accessioned | 2010-06-30T10:47:21Z | - |
dc.date.accessioned | 2018-06-28T17:39:03Z | - |
dc.date.available | 2010-06-30T10:47:21Z | - |
dc.date.available | 2018-06-28T17:39:03Z | - |
dc.date.issued | 2008 | - |
dc.identifier.other | U0001-1507200812261200 | en |
dc.identifier.uri | http://ntur.lib.ntu.edu.tw//handle/246246/187298 | - |
dc.description.abstract | 迴路式熱管(Loop Heat Pipe, LHP)數學模型的建立可以幫助設計以及性能上的預測。然而,早期文獻僅針對個別元件進行分析及模擬,甚至忽略考慮毛細結構的相變化熱傳,並且將毛細結構視為單一平均孔徑,這些假設會使模型的適用範圍與應用空間大幅減小。因此,本文將毛細結構的相變化熱傳以及孔徑分佈的概念皆納入考量,建立一穩態模型,能夠廣泛的預測單孔徑與雙孔徑毛細結構於迴路式熱管中,不同輸入熱量下之補償室與蒸發器壁面溫度。經實驗與預測結果比較,最大誤差不超過23%。 在模型的預測中,利用毛細結構臨界孔徑的方法,來討論毛細結構的孔徑分佈對性能的影響。分析結果顯示,孔徑分佈的不同會影響毛細結構內蒸氣累積的情況,而蒸氣薄膜的發生是影響熱傳性能的主要原因,藉由蒸氣薄膜熱阻與系統總熱阻的比值,可做為判斷毛細結構性能的指標,以及性能提升的依據。其中,單孔徑毛細結構因孔徑分佈較窄,蒸氣排除不易,產生之蒸汽薄膜的熱阻會隨輸入瓦數的增加而升高,當輸入熱量達500W時,蒸汽薄膜熱阻高達0.16℃/W,占系統總熱阻(0.26℃/W)60%。 由於雙孔徑毛細結構具有能排除蒸氣的大孔,受到蒸氣薄膜影響的程度較小,藉由模型分析大孔之數量與尺寸對系統性能的影響,可知在大孔尺寸較小、數量較多的情況下,具有較佳的熱傳性能,其中最佳之雙孔徑毛細結構,蒸氣薄膜的熱阻減少至0.002℃/W,占系統熱阻(0.1℃/W)的2%,顯示毛細結構之性能已達上限,說明利用雙孔徑毛細結構可有效降低蒸汽薄膜熱阻,提升迴路式熱管熱傳性能。 | zh-TW |
dc.description.abstract | A mathematical model for Loop heat pipes (LHPs) can provide a straightforward method of design analysis and performance improvement. However, most of mathematical models were developed for the specific component, either for a wick or a compensation chamber. These models ignored the phase-change heat transfer or the pore size distribution of a wick structure. It will restrict the range of application and prediction of the model. An improved 1-D steady state model was developed in this study. The phase-change heat transfer and the pore size distribution of a wick structure were also taken into account. The evaporator surface temperature was calculated as a function of the heat load. Both of the monoporous wick and biporous wick can also be predicted, the comparison between the predicted results and experimental data are within 23%. The effects of pore size distributions in the wick’s performances were studied by this model. Results of this study showed the different pore size distributions will influence the vapor blanket extent of the wicks, which can be estimated by the thermal resistance. This thermal resistance dominates the heat transfer performance of the wick and thus can be considered as a standard for the wick’s heat transfer capacity. Because the narrow pore size distribution of the monoporous wick would accumulate gradually to form the vapor blanket, it brings the higher thermal resistance with increasing heat flux. As the heat load increased to 500W, the thermal resistance of the vapor blanket would reach to 0.16℃/W, and 60% of the total thermal resistance(0.26℃/W). The large pores in the biporous wick play the role as the path way for vapor to escape, and thus the performance is affected less by the vapor blanket. The size and amount of larger pores in the biporous wicks was analyzed to investigate the heat transfer capacity of the LHP by this model. The Results indicate that the large pores with reducing size and increasing amount have better performance. The optimized biporous wick can obviously reduce the thermal resistance of vapor blanket to 0.002℃/W, only 2% of the total thermal resistance(0.1℃/W), on the other hand, the biporous wick can not only effectively eliminate the thermal resistance of vapor blanket but also improve the heat transfer capacity of the LHP. | en |
dc.description.tableofcontents | 誌謝 ii要 ivbstract vi錄 viii目錄 xii目錄 xiv號說明 xvi一章 緒論 1.1前言 1.2文獻回顧 5.2.1系統操作溫度預測模型 5.2.2毛細結構熱傳模型 6.3研究目的 12二章 迴路式熱管基本原理 13.1迴路式熱管的基本描述 13.2系統操作原理 13.2-1毛細限制 14.2-2啟動限制 15.2-3液體過冷限制 16.2-4補償室體積限制 16.3迴路式熱管系統之熱阻 17三章 穩態模型 21.1數學模型的假設 21.2能量流動分析 22.3流動壓降分析 23.4輸入及輸出參數 25.5模型計算流程 25.5-1工作流體性質 28.5-2系統管路單相壓降與熱傳之計算 28.5-3系統管路二相壓降之計算 30.5-4系統管路二相熱傳之計算 32.5-5毛細結構壓降與熱傳 34.6蒸發器至補償室間之熱傳 34.6-1熱洩漏量之計算 34.6-2過冷液回流熱量的計算 36.6-3補償室與環境之熱交換 37四章 毛細結構相變化熱傳模型 39.1毛細結構模型概要說明及假設 39.2模型計算流程 40.3數學模型之統御方程式 42.4相對滲透度及毛細壓力之關係 43.4-1毛細結構孔徑與二相流動之關係 43.4-2孔徑分佈曲線與相對滲透度之關係 44.4-3能量與動量方程式之結合條件 46.4-4具蒸汽薄膜之狀態 47.5模型流程圖 49五章 實驗流程與原理 51.1迴路式熱管熱傳性能的量測 51.2毛細結構參數量測 52.2-1滲透度 52.2-2孔隙度及孔徑分佈 52.3誤差分析 56.4實驗參數 56六章 結果與討論 57.1穩態模型預測結果 57.2預測結果之分析 60.3穩態模型的應用與參數探討 62.3-1蒸汽薄膜發生原因 63.3-2降低蒸汽薄膜影響方法之討論 65.4性能測試 76七章 結論與建議 78.1結論 78.2建議 80考文獻 82錄 88 | en |
dc.format.extent | 4689550 bytes | - |
dc.format.mimetype | application/pdf | - |
dc.language | zh-TW | en |
dc.language.iso | en_US | - |
dc.subject | 迴路式熱管 | zh-TW |
dc.subject | 孔徑分佈曲線 | zh-TW |
dc.subject | 單孔徑毛細結構 | zh-TW |
dc.subject | 雙孔徑毛細結構 | zh-TW |
dc.subject | 相變化熱傳 | zh-TW |
dc.subject | Loop heat pipe | en |
dc.subject | pore size distribution | en |
dc.subject | monoporous wick | en |
dc.subject | biporous wick | en |
dc.subject | phase-change heat transfer | en |
dc.title | 具毛細結構相變化熱傳效應之迴路式熱管數學模型 | zh-TW |
dc.title | Mathematical Model of a Loop Heat Pipe with Phase-Change Heat Transfer in a Wick Structure | en |
dc.type | thesis | en |
dc.identifier.uri.fulltext | http://ntur.lib.ntu.edu.tw/bitstream/246246/187298/1/ntu-97-R95522312-1.pdf | - |
item.openairecristype | http://purl.org/coar/resource_type/c_46ec | - |
item.openairetype | thesis | - |
item.languageiso639-1 | en_US | - |
item.grantfulltext | open | - |
item.cerifentitytype | Publications | - |
item.fulltext | with fulltext | - |
顯示於: | 機械工程學系
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