臺灣博碩士論文加值系統

利用擋板不同的傾斜角度、位置、大小來改變流場分佈，使散熱模組的散熱性能提升即是本次研究之目標。針對散熱座本身之熱傳現象進行改善，限制流過鰭片末端處的流體，使鰭片底部、溫度較高處可以獲得較大之流場速度，以高溫表面與高速流體相配合來提升散熱性能，此流場速度之差異即本文研究之對象，本文將其定義為流場之非均勻性。本次研究在散熱座前方裝置一擋板，透過擋板的傾斜以影響流場而達到預求之流場分佈，進而改變散熱座之散熱性能。研究結果發現，在不同的擋板傾斜方式與角度之下，散熱性能最多可以獲得5.8％的提升，進一步透過擋板的移動，可以使散熱性能的改善量提升至8.7％；改變擋板的大小會對散熱性能產生不同的影響，改變得宜可使散熱性能提升13.6％，反之則會使散熱性能下降4.1％之多；由於擋板傾斜、移動所產生的開口，使模組之散熱性能得以提升，若將鰭片高度調整至較適合之狀況，可以提升21.4％的散熱性能。在獲得散熱性能提升的同時，必須付出的代價是額外增加的壓力損失，其與散熱性能呈現正相關的變化；在散熱能力與輸入送風功率之間如何取捨以得到符合設計者要求之條件，可透過本研究之結果來決定。

In this study, the aim is to enhance the performance of a thermal module with improving the fluid field by a plate with different slanted angles, positions and sizes. It is focused on improving thermal performance with a strong fluid field near the bottom of a heat sink by limited the fluid flow around the top of the fin. Supplying the high fluid velocity over the high temperature surface will enhance the cooling ability of the thermal module. The varied fluid velocity is an important factor for the level of the non-uniform fluid field in this study. To reach the goal, the fluid field influenced by a slanted plate in front of the heat sink. Investigated results show that the thermal performance is increased 5.8％ with varied slanted angles. By adjusting the plate to appropriate position, the performance were raised 8.7％. There is a 13.6％ enhancement of the thermal performance if the size of the plate is changed appropriately. The inappropriate size of the plate will decrease the thermal performance about 4.1％. Base on the right slanted type, position and size, the maximum enhancement on the performance of the thermal module is 21.4％ in characteristic height of fin. The increasement of the pressure loss depends on the variation of the thermal performance. Regarding the compromise between the thermal performance and the pressure loss, designers may select what they need by the results of this study.

誌謝 i
摘要 ii
Abstract iii
目錄 v
圖目錄 viii
表目錄 xv
符號索引 xvi
第一章 緒論 1
1.1 前言 1
1.2 文獻回顧 4
1.3 研究動機 8
1.4 研究目的 11
第二章 理論分析 12
2.1 物理模型 13
2.2 基本假設 14
2.3 統御方程式 15
第三章 數值方法 22
3.1 差分方程式的建立 22
3.2 流場空間的離散體系 26
3.3 網格點系統 28
3.4 數值方法的求解流程 29
3.4.1 SIMPLE法 30
3.4.2 SIMPLEST法 32
3.5 收斂條件 33
3.6 格點獨立系統 34
第四章 結果與討論 36
4.1 不同擋板傾斜方式的影響 37
4.1.1 固定中心點使擋板傾斜 37
4.1.2 固定右端點使擋板傾斜 40
4.1.3 固定左端點使擋板傾斜 42
4.2 擋板不同位置與大小的影響 43
4.2.1 將擋板朝流道上端靠近 44
4.2.2 擋板大小的影響 46
4.3 擋板開口與鰭片高度的關係 48
4.3.1 流場分佈均勻之傳統流道 48
4.3.2擋板開口為10 mm時散熱座鰭片適合之高度 49
4.3.3擋板開口為5 mm時散熱座鰭片適合之高度 52
第五章 結論與展望 55
5.1 結論 55
5.2 未來展望 56
參考文獻 58

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