臺灣博碩士論文加值系統

本研究為觀測在具有圓弧彎道之透明圓管內，以氮氣驅動非牛頓流體之流場流型實驗。實驗藉由氮氣的注入形成一連續延伸之長氣泡來驅動圓管內之非牛頓流體，並觀測其於圓管內前進所產生之雙流體擠壓流型。進而探討此一長氣泡通過圓弧彎道時的其所產生之擠壓輪廓與流型以及其穿透行為。
本實驗藉由改變圓弧彎道角度、非牛頓流體黏度、氣體流量並配合影像擷取進行擠壓流之觀測與分析。本研究所採用之圓弧彎道分別為90度、135度與180度，圓管直徑為8 mm，曲率為0.005 ，氮氣流量分別為200、600與1000 ml/min。
由實驗結果可歸納出，在距氣泡尖端約6倍管直徑時，氣泡寬度將趨於定值。並在此基礎下，導入偏心率來解析氣泡在圓弧彎道內之偏移情形，本研究發現在流體黏度、彎管角度相同時，流量越高偏心率也會越大，反之越小。於探討毛細係數及威森堡數兩者與偏心率間之關係發現，氣泡在彎管前端之偏心率隨著毛細係數及威森堡數的增加而增加，為正比之關係。

The experiment performed the flow visualization by using nitrogen gas to drive the non-Newtonian fluids in a curved circular tube. A continuous long gas bubble was formed to expel the non-Newtonian fluids in the curved tube. Observation of the flow patterns in the curved region, the penetration behavior and leading edge contour of the long bubble were studied.
The controlling variables of the experiments are the curving angle of the circular tube, the viscosity of the fluids and the volumetric flow rate of the injected gas. The images of the twin flow were taken and analyzed. The curving angles of the tubes are 90ﾟ, 135ﾟand 180ﾟ. The diameter and the curvature of the tube are 8.0 mm and 0.005 , respectively. The flow rates of the Nitrogen gas are 200, 600 and 1000 ml/min.
The results of the experiments showed that the bubble width approaches constant value at the location six-diameter upstream from the bubble front. A difference variable is introduced at the six-diameter location to show the shifting deviation of the bubble in the curved tube. It is shown that, with the same fluid viscosity and the curving angle, the difference is higher when the gas flow rate is higher. Also, the difference increases proportionally when the Capillary number and the Weissenberg number increase.

目錄
中文摘要 I
英文摘要 II
誌謝 III
目錄 IV
圖目錄 VII
表目錄 IX
符號說明 X

第一章　緒論 1
　 1-1前言 1
　 1-2研究背景與目的 4
　 1-3文獻回顧 5

第二章　實驗量測系統與方法 9
　 2-1概論 9
　 2-2實驗系統元件 10
2-2.1壓力控制單元 10
2-2.2連接用之三通管 11
2-2.3雙層壓克力管 11
2-2.4光照設備 12
2-2.5影像拍攝設備 12
　 2-3實驗方法與步驟 13
2-3.1溫度控制 13
2-3.2彎管定位 13
2-3.3充填流體 13
2-3.4壓力控制 14
2-3.5控制光源 14
2-3.6充氣 14
2-3.7影像擷取 15
2-3.8後設動作 15
2-3.9速度的計算 16
2-3.10實驗流程 16
　 2-4牛頓流體與非牛頓流體 18
　 2-5非牛頓流體介紹 20
2-5.1冪次流體(Power-Law Fluid) 20
2-5.2黏彈性流體(Viscoelastic Fluid) 21
2-5.3賓漢流體(Bingham Fluid) 21
　 2-6實驗流體 22
2-6.1羧甲基纖維素CMC (Csrboy Methyl Cellulose) 22
2-6.2聚丙烯醯胺PAA (Polyacrylamide) 23
2-6.3聚丙烯酸鈉 PAS(Polyacrylic Acid Sodium) 25
2-6.4實驗流體性質 25
　 2-7實驗誤差 27

第三章　實驗結果與討論 39
　 3-1速度分析 39
　 3-2影像處理 46
3-2.1影像軟體與MATLAB影像處理 46
3-2.2分析位置 47
　 3-3偏心率 51
3-3.1偏心率定義 51
3-3.2氣泡形狀 52
3-3.3偏心率分析結果 54
　 3-4毛細係數與威森堡數 61

第四章　結論 64

第五章　未來展望 65

參考文獻 66

附錄 69

簡歷 78

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