臺灣博碩士論文加值系統

此篇研究中以實驗的方式研究垂直圓管上升氣水雙相流流譜量測與鑑別，利用壓力信號以及電導度信號量測信號並進行其特性分析，並且設有觀測段可供高速攝影機照相、攝影作為對比使用。由於目前尚未有一套完整偵測流譜信號的方法，故透過建立大量的實驗數據庫，並對實驗範圍內各種不同流譜進行流譜特性分析，希望能夠得到統一且客觀的雙相流流譜鑑別方法用於非侵入式的感測器偵測。
本研究將專注於散佈型氣泡流的流譜特性分析，散佈型氣泡流最大的特徵是氣泡大小均勻且分布均勻的流譜，但是在過去的研究中，許多學者都把散佈型氣泡流歸納在氣泡流中的一部分，如著名的Mishima and Ishii[1]雙相流流譜。故本研究將嘗試使用密度機率分佈圖模組參數化來鑑別散佈型氣泡流與其他流譜之邊界。在散佈型氣泡流分析上，發現其有震動的現象，本研究將其震動信號與小氣泡信號分開討論且分析，並探討其速度的變化與表面氣水流速之關係。本研究也發展出一套計算散佈型氣泡流之氣泡大小的方法，並與可視化影像作為驗證，已證實此方法是可以計算出其氣泡大小。
本研究針對散佈型氣泡流做一相當深入的探討，不僅在判別散佈型氣泡流與其他流譜之差異並與過去學者之研究相互印證，其特性分析對於未來在鑑別流譜上亦扮演著非常重要的角色。

In this study, the pressure signals and conductivity sensors are used to analyze the characteristics of the upward air-water two-phase flow and there is an observed section that provides a high-speed camera for photography.
This study will focus on the analysis of the flow pattern characteristics of the dispersed bubbly flow. The characteristic of the dispersed bubbly flow is that the flow pattern with uniform bubble size and uniform distribution. However, in the past researchs, many scholars reduced the dispersed bubbly flow. to the bubbly flow, such as the Mishima and Ishii two-phase flow pattern. This study will try to use the probability density function parameterization to identify the boundary between the dispersed bubbly flow and the other flow patterns. In the analysis of dispersed bubbly flow, it was found that there is vibration in the dispersed bubbly flow. The vibration signal and the small bubble signal are discussed separately and analyzed, and the relationship between the velocity and the superficial velocity is discussed. This study also developed a method for calculating the bubble size of a dispersed bubbly flow, and with the visualization as a verification, it has been proved that this method can calculate the bubble size.

摘要 iii
Abtract v
目錄 vii
圖目錄 x
表目錄 xv
符號說明 xvi
第一章 緒論 1
1.1 前言 1
1.2 雙相流簡介 2
1.2.1 雙相流基本性質 2
1.2.2 流譜分類(flow regime/ flow pattern) 2
1.3 研究目的與方法 5
第二章 文獻回顧 6
2.1 垂直雙相流流譜圖 6
2.2 散佈型氣泡流流譜之邊界轉換機制 9
第三章 實驗系統與實驗步驟 14
3.1 實驗設備 14
3.1.1 空氣供給系統 15
3.1.2 冷水供給系統 16
3.1.3 流譜測試段系統 17
3.1.4 量測信號系統 20
3.1.5 資料擷取系統 21
3.2 實驗流速範圍 22
3.3 實驗步驟 23
第四章 分析方法 25
4.1 空泡分率信號 25
4.2 機率密度分佈圖 28
4.3 PDF模組參數化 29
4.4 PDF雙峰模組參數化 33
4.5 PDF雙峰模組參數化流譜圖驗證 35
4.6 散佈型氣泡流流譜之邊界 37
4.7 散佈型氣泡流訊號分析 43
4.7.1 散佈型氣泡流之特性分析 43
4.7.2 散佈型氣泡流之氣泡速度與氣泡大小 49
第五章 結果與討論 56
5.1 散佈型氣泡流之流譜邊界 56
5.2 散佈型氣泡流之特性分析 63
5.2.1 散佈型氣泡流之速度分析 63
5.2.2 散佈型氣泡流之氣泡大小 72
第六章 結論 75
6.1 研究成果 75
6.2 未來研究建議 76
參考文獻 78

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