測量過渡或紊流噴泉在密度界面層之穿透性捲增流量的新實驗設計

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研究生：	Alviani Hesthi Permata Ningtyas Alviani - Hesthi Permata Ningtyas
論文名稱：	測量過渡或紊流噴泉在密度界面層之穿透性捲增流量的新實驗設計 A new experimental design to measure the penetrative entrainment flow rate due to a transition or turbulent fountain at a density interface
指導教授：	林怡均 Yi-Jiun Peter LIN
口試委員:	戴璽恆 Albert Dai 田維欣 Wei-Hsin Tien
學位類別：	碩士 Master
系所名稱：	工程學院 - 機械工程系 Department of Mechanical Engineering
論文出版年：	2016
畢業學年度：	104
語文別：	英文
論文頁數：	139
中文關鍵詞：	密度界面、紊流噴泉、穿透性捲增。
外文關鍵詞：	Density interface, turbulent fountain, penetrative entrainment.
相關次數：	點閱：334 下載：9
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藉由本噴泉產生的穿透性捲增在自然界中有許多實際上的應用, 其中包括商用大樓的冷卻系統, 與改善水質的循環式儲水系統等。本研究量化探討穿透性捲增的體積流量, 利用新的實驗設計估算噴泉在密度界面層之穿透性捲增的體積流量。實驗使用鹽浴技術, 鹽水源與清水源分別置於壓克力模型內不同的高度位置, 清水源位於模型頂部, 鹽水源利用壓克力管位於模型底部上方2 cm 處。本研究總共有九組實驗, 其中有三組實驗, 清水源的流體撞擊到壓克力模型底部邊界。本研究採用兩種資料擷取方法包括密度量測與影像擷取。實驗的初始情況為兩分層流體, 上層為清水, 下層為經過染色處理的鹽水, 實驗開始之後, 上層流體的密度會隨著時間而增加, 直到實驗達到穩態時, 上層流體的密度趨近於定值。而在暫態時下層流體的密度為定值, 除了清水源撞擊壓克力模型底部邊界的實驗, 這些實驗, 下層流體的密度會低於鹽水源溶液的密度, 造成密度層界面不甚明顯。對於清水源流體沒有撞擊到模型底部邊界的實驗, 此實驗設置提供三個獨立方程式估算噴泉產生的穿透性捲增的體積流量, 使用紊流噴泉模型估算, 當初始噴流動量為4/3 Q2f/A 時, 密度界面層的理察遜數範圍在0.029到1.816之間, 捲增率範圍在0.13到2.21之間, 當初始噴流動量為Q2f/A 時, 密度界面層的理察遜數範圍在0.044到14.389之間, 捲增率範圍在0.12到2.08之間。

Penetrative entrainment by a turbulent fountain has many practical applications
in nature. The examples include the cooling system in the commercial building,
recirculating a water reservoir and the process of improving the water quality.
This research studied the penetrative entrainment ﬂow rate quantitatively. A
new experimental design was developed to estimate the penetrative entrainment
volume ﬂow rate by a turbulent fountain.
Simulation experiments used the salt bath technique. Two sources, a salt solution source and a fresh water source, were placed in a plexiglass tank. Two
sources were located at diﬀerent heights, the fresh water source at the top and the salt solution source at 2 cm above the ﬂoor of the tank. There were 9 experimental runs conducted in this research, and the ﬂow from the fresh water source hit the ﬂoor boundary in 3 runs of them. Two data acquisition methods included the measurements of solution density and the recording of ﬂow images.
Experiments started from the 2 layers initially with the fresh water as the
upper layer and the salt solution as the lower layer. After the experiment began,
the density in the upper dilute layer increased with the time until the steady state
and the density in the lower dense layer remained the same in the transient state
except for the cases in which the fountain ﬂow hit the ﬂoor boundary. When the
fresh water ﬂow hit the ﬂoor boundary, the density of the lower dense layer was less than that of the salt solution and the interface was unclear. For the experimental cases in which the fountain ﬂow does not reach the ﬂoor, this new experimental set-up gives three independent equations to estimate the penetrative entrainment ﬂow rate by a fountain ﬂow. Using the numerical turbulent fountain ﬂow model gives the Richardson number at the density interface between 0.029 and 1.816 and the entrainment rate in the range between 0.13 and 2.21, when the initial fountain momentum is 4/3 Q2f/A , and the Richardson number at the density interface between 0.044 and 14.389 and the entrainment rate in the range between 0.12 and 2.08, when the initial fountain momentum is Q2 /A .

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
List of Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Introduction 1
1 Background and Purpose for this Study . . . . . . . . . . . . . . . . 1
2 Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3 Flow Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 The Outline of the Thesis . . . . . . . . . . . . . . . . . . . . . . . 7
Theoretical Analysis 9
1 Theoretical Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2 Penetrative Entrainment Flow Rate Estimations . . . . . . . . . . . 12
Experiments 15
1 Arrangement of The Water Flow . . . . . . . . . . . . . . . . . . . 15
1.1 Rotameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.2 Experimental Tank . . . . . . . . . . . . . . . . . . . . . . . 16
1.3 Constant Head Tanks . . . . . . . . . . . . . . . . . . . . . . 16
1.4 Siphon Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2 Digital Image Recording . . . . . . . . . . . . . . . . . . . . . . . . 17
3 Experimental Runs . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4 Data Collection and Processing Approach . . . . . . . . . . . . . . 19
4.1 Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.2 Data Processing Approach . . . . . . . . . . . . . . . . . . . 20
5 Lambert Beer Law . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Experimental Results 23
1 Two Series of Experiments . . . . . . . . . . . . . . . . . . . . . . . 23
2 The Process To The Steady State . . . . . . . . . . . . . . . . . . . 24
3 The Density Measurements . . . . . . . . . . . . . . . . . . . . . . . 25
3.1 Experimental Measurements . . . . . . . . . . . . . . . . . . 25
3.2 Comparisons with Theoretical Predictions . . . . . . . . . . 29
4 The Light Intensity Data . . . . . . . . . . . . . . . . . . . . . . . . 31
4.1 Experimental Data . . . . . . . . . . . . . . . . . . . . . . . 31
4.2 Weighted Intensity Slope . . . . . . . . . . . . . . . . . . . . 31
5 Interface Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
6 Penetrative Entrainment Flow Rate . . . . . . . . . . . . . . . . . . 34
6.1 Experimental Results . . . . . . . . . . . . . . . . . . . . . . 34
6.2 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7 Richardson Number and Entrainment Rate . . . . . . . . . . . . . . 38
Conclusions and Suggestions 41
1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2 Suggestions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
References 45
Table 47
Figure 65
Curriculum Vitae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

                                

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