臺灣博碩士論文加值系統

本實驗採用之氣泡床為內徑80 mm、高500 mm之透明壓克力圓管；並使用粒徑為1.7 mm之玻璃珠當作固體粒子。壓力探針置於分散器上方5、20、40 cm處，用以量測壓力擾動訊號。探討不同表面液體流速、不同起始液體高度及不同固體負荷量下對平均壓差與壓力擾動標準偏差值的影響。並用傅立葉轉換(Fourier transform)來分析功率頻譜密度函數主頻之變化，與小波轉換(wavelet transform)分析原始壓力擾動訊號。
實驗結果顯示，隨著表面氣體速度的增加，氣泡床中的流態從氣泡均勻分散區轉變為過渡區，再從過渡區轉變為氣泡不均勻分散區。又經快速傅立葉轉換(FFT)，隨著表面氣體速度的增加，主頻會往高頻率方向移動，而在不同流態下會顯示出不同的主頻。而經小波轉換(wavelet transform)後，將原始壓力擾動訊號依不同的頻率大小分成不同的尺度，其中幾個尺度標準偏差值的變化，亦可與氣泡床的流態變化情形相對應。可知小波轉換提供了一個新方法對於判斷氣泡床的流態變化。

中文摘要 Ⅰ
英文摘要 Ⅱ
目錄 Ⅳ
圖索引 Ⅵ
表索引 Ⅹ
第一章 緒論……………………………………………………1
第二章 文獻回顧………………………………………………3
2.1 氣-液兩相氣泡床及氣-液-固三相流體化床的分類………….3
2.2 氣體分散器的種類………………………………………………7
2.3 氣泡床中之巨觀流動結構………………………………..……8
2.4 氣泡破裂與凝聚機構………………………………….………12
2.5 氣-液-固三相流體化床的應用…………………….…………13
2.6 小波轉換(wavelet transform)簡介…………………………15
第三章 實驗裝置與步驟……………………………………18
3.1 實驗裝置……………………………………………………18
3.2 反應器三相之性質…………………………………………22
3.3 實驗步驟……………………………………………………24
3.3-1. 起始液體高度的響………………………………...24
3.3-2. 表面液體流速的響………………………………...24
3.3-3. 固體負荷量的響…………………………………...24
3.3-4. 功率頻譜密度函數及主析……………....……...25
3.3-5. 小波轉換及其分析…… ……………………......25
3.4 數據分析……………………..……………………………28
3.4-1. Fourier transform….…………………………...28
3.4-2. wavelet transform…………………….………...29
第四章 結果與討論…………………………………………...35
4.1 起始液體高度的影響……………………………………………35
4.2 表面液體流速的影響……………………………………………38
4.3 床中軸向不同位置之流態………………………………………44
4.3-1. 探針置於分散器上方20 cm處………………………………44
4.3-2. 探針置於分散器上方40 cm處………………………………44
4.3-3. 軸向不同位置之結果……………………………………….49
4.4 固體粒子負荷量的影響…………………………………………49
4.5 傅立葉轉換(Fourier transform)之分析…….………….… 55
4.6 小波轉換(wavelet transform)之分析……………...………69
4.7 氣-液兩相氣泡床之流態圖(Flow regime map)………………80
第五章 結論……………………………………………………83
符號說明…………………………………………………………85
參考文獻…………………………………………………………87
附錄………………………………………………………………92

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