臺灣博碩士論文加值系統

隨著國民所得及生活水準與品質逐年提昇，家用冰箱市場普及率高達99%。在節能的要求與產品競爭力雙重壓力下，高效能冰箱的研發成為目前急需進行的工作。本研究運用實體溫度量測整合計算流體力學方法，解析整體冰箱於運轉情況下三維熱流場之分佈。研究結果除了可供設計開發之參考外，亦使產品的開發更具時效性與經濟效益。
溫度量測系統係利用T型熱電偶量測，並透過數據擷取器記錄冰箱內部各點溫度溫度隨時間的變化；量測點包括風扇口、冷凍室、冷藏室、蔬果室、進風口、回風口、內壁溫度等。數值模擬係利用套裝軟體STAR-CD，以有限容積法解析整體冰箱之三維熱流場。模擬包含流體及固體兩個部份；流體部份，係以質量、動量及能量守恒方程式解析速度及溫度，固體部分則用共結式熱傳方程式解析溫度分佈。最後依實驗與模擬兩者所得數據進行交叉比對，探討數值模擬應用於研究整體冰箱的適用性及對影響整體熱傳效應變數作出定性的評估。
透過模擬與實驗的交叉比對，在冷凍室與冷藏室之間均得到理想的結果，不過在壁面溫度的掌握上，並沒有相當的精確；原因在於受到內嵌式冷凝管的影響，無法得到冷凝管在壁內的正確位置及深度。未來可朝向利用熱影像分析儀拍攝壁面溫度以設定準確的邊界條件。論文最後依模擬與實驗所得熱流場趨勢，提出五點建議作為未來冰箱在改良設計及模擬研究之參考，以期許數值模擬應用於冰箱科學上更趨於準確也更具參考價值。

Due to the demands of energy-saving and product competition, the development of a highly efficient refrigerator becomes a very urgent job at present.
The objective of this research is to combine direct experimental measurements with computational fluid dynamics modeling to study the thermal fluid phenomena in a domestic refrigerator. Experiments were carried out on a real refrigerator. Thermocouples were fixed inside the refrigerator, including freezer compartment, fresh food compartment and fruit area. The output signals from the thermocouples were connected to a computer-based data acquisition system.
The computational fluid dynamics model was built to simulate the thermal and flow fields of the refrigerator. Computational fluid dynamics based on the finite volume method was employed to investigate the thermal and fluid fields, which include flow velocity and temperature distributions. The simulated model included the freezer compartment, fresh food compartment, separating plates, and flow passages. For the fluid domain, equations of conservation of mass, momentum, and energy were solved to obtain the temperature, pressure and velocity distributions. Conjugate heat transfer was utilized to comprehend the thermal fields of the solid domain. Thus temperature distributions of solid segments were also computed. The parameters, which are detrimental to the overall heat transfer efficiency, such as conduction, natural and forced convection, flow passage design, and volume flow rate, were investigated.
Experimental measurements have also been used to verify the CFD model and gain a better understanding of the thermal and flow fields. The CFD model have been shown to be accurate in general. However, there are areas where the accuracy is less than satisfactory. The reasons for this may be attributed to not enough information about the wall temperature. At last, five proposals for improving the outcomes of simulations are recommended.

誌謝……………………………………………………………………….Ⅰ
摘要……………………………………………………………………….Ⅱ
ABSTRACT……………………………………………….……………...Ⅲ
目錄……………………………………………………………………….Ⅴ
表錄……………………………………………………………………….Ⅷ
圖錄……………………………………………………………………….Ⅸ
符號說明……………………………………………………………….ⅩⅡ
一、緒論…………………………………………………………………….1
1.1研究動機………………………………………………………..…...1
1.2文獻回顧……………………………………………………….……2
二、實驗設備與量測……………………………………………………….8
2.1冰箱實體…………………………………………………………….8
2.2溫度量測系統……………………………………………………….9
2.3實驗步驟…………………………………………………………...10
三、數值模擬……………………………………………………………..13
3.1模型建構…………………………………………………………...13
3.1.1幾何結構………………………………………………………13
3.1.2數值計算格點建立……………………………………………14
3.1.3計算流體力學…………………………………………………15
3.2流體性質……………………………………………………….…..16
3.3邊界條件…………………………………………………………...16
3.4初始條件…………………………………………………………...16
3.5材料性質…………………………………………………………...16
3.6數值計算…………………………………………………………...17
3.7後處理結果輸出………………………………………………….. 17
四、數值分析理論………………………………………………………..23
4.1基本守恆方程式…………………………………………...………23
4.1.1質量及動量守恆………………………………………...…….23
4.1.2能量守恆………………………………………………………24
4.1.3共結式熱傳導…………………………………………………25
4.2有限容積法………………………………………………………...25
4.3演算法……………………………………………………………...29
五、結果與討論…………………………………………………………..34
5.1實驗量測結果………..…………………………………………….34
5.1.1冷凍室…………………………………………………………34
5.1.2冷藏室…………………………………………………………35
5.1.3蔬果室…………………………………………………………36
5.1.4數據整理………………………………………………………37
5.2數值模擬結果……………………………………………………...37
5.2.1冷凍室…………………………………………………………37
5.2.2冷藏室…………………………………………………………38
5.2.3蔬果室…………………………………………………………39
六、結論與未來展望…………………………………………………….56
6.1結論……………………………………………………………...56
6.2未來展望………………………………………………………...57
參考文獻………………………………………………………………….58

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