本論文旨在利用冷卻水塔的噪音防制為例，來研究開發發泡鋁板的應用。本研究係藉由架設隔音牆的方式來阻隔其聲音的傳播，然聲波傳播至隔音牆邊界時會產生繞射現象，故本論文首先將應用Hayek所建立之隔音牆繞射數學模式，來分析聲音傳播路徑，並以此為理論基礎，進行發泡鋁板與隔音牆之研究。
在實驗上，首先利用聲強法對冷卻水塔進行量測，計算各聲源之聲功率，藉此判定其主要噪音源。經對其進行頻率分析後，以冷卻水塔上部之風扇馬達為主要噪音源，且其頻率範圍為25 Hz至2500 Hz，故將選用具有全頻域隔音性質之AP板為隔音牆材料。
在確定主要噪音源後，即進行隔音牆之研究，本論文之隔音牆為配合現場環境，故設計U字形隔音牆（鳥瞰圖）將冷卻水塔包覆於其中，即留下靠牆面未設立隔音牆，此隔音牆以鋁板為襯板，而將發泡鋁板附加於隔音牆上層。為研究噪音源在隔音牆之上層邊界的繞射現象，本研究分別在隔音牆上貼附發泡鋁板層以增加邊界的厚度，量測其結果，並比較分析各種情況之隔音效果。且又以設計T形造型之隔音牆，探討其實用性。最後之量測結果是以鋁隔音牆上層全面附加複合板的隔音效果最佳，將整體環境之噪音值降至59 dB，而符合噪音管制標準。

This thesis uses aluminum porous board (AP board) to study the noise reduction for cooling tower. It sets the barrier to isolate the sound propagation. But it will happen diffracted phenomenon when sound wave impinging at the edge of barrier. So the mathematical model of acoustic diffraction on the barriers, which is set up by Hayek, is applied in this thesis. Base on this theorem, the AP board and the paths of sound propagation are analyzed.
In experiment, it uses the sound intensity method to measure the cooling tower for determining the major source first. The major source is determined by ranking the sound power. And the suitable insulation material is selected by analysis the frequency band of major source. After analyzing, the major source of cooling tower is the region of fans by motor driven that is located upper the cooling tower. And its frequency range is between 25 Hz to 2500 Hz. So the AP board is a candidate since it has broadband characteristic on noise insulation.
After aim of the major source, the noise barrier is studied for noise reduction. In this thesis, the U profile of barrier (looking down from above), which considers the situation in the field, is designed to surround the cooling tower. This barrier is made of aluminum board, and the aluminum porous board is applied to add on the upper barrier for noise reduction. To study the acoustic diffraction on the boundary of barrier, the thick of porous board is added on the upper barrier. The insulation effect is compared in the different condition after measuring the transmission loss. The T shape barrier is also designed for noise reduction evaluating in this thesis. Finally, the best-insulated effect is obtained when the complex board is added on the upper barrier. And the noise level is down to 59 dB around the environment. This result is matched the EPA noise standards.

目錄

目錄………………………………………………………………………I
表目錄……………………………………………………………………V
圖目錄……………………………………………………………………VI
中文摘要…………………………………………………………………X
英文摘要…………………………………………………………………XI
第一章 緒論……………………………………………………………1
1.1 簡介………………………………………………………………1
1.1.1 何謂噪音……………………………………………1
1.1.2 噪音防制……………………………………………1
1.1.3 冷卻水塔……………………………………………5
1.1.3.1 冷卻水塔之原理…………………………………6
1.1.3.2 冷卻水塔之結構…………………………………7
1.1.3.3 冷卻水塔之種類…………………………………8
1.2文獻回顧……………………………………………………………9
1.2.1 繞射理論回顧……………………………………9
1.2.2 隔音牆外形簡介………………………………10
1.3研究動機…………………………………………………11

第二章 基本理論………………………………………………………18
2.1聲強法………………………………………………………18
2.1.1聲強之原理…………………………………………19
2.1.2 聲強探頭……………………………………………21
2.1.3量測方式……………………………………………21
2.1.4聲強法之測量方式…………………………………22
2.1.5背景噪音之影響……………………………………23
2.1.6聲強法的限制………………………………………23
2.2隔音牆聲場理論……………………………………………25
2.2.1 入射聲壓……………………………………………26
2.2.1.1 點聲源………………………………………26
2.2.1.2 線聲源………………………………………27
2.2.2 反射聲壓……………………………………………29
2.2.3 繞射聲壓……………………………………………31

第三章 冷卻水塔噪音量測實驗設定…………………………46
3.1實驗法規及驗收標準………………………………………46
3.1.1噪音量測法規………………………………………46
3.1.2 隔音牆驗收標準…………………………………49
3.2冷卻水塔之聲強量測………………………………………50
3.2.1 量測儀器……………………………………………50
3.2.1.1 聲強量測儀與聲強探頭組…………………50
3.2.1.2 聲強校正器…………………………………51
3.2.2 量測方法及程序…………………………………52
3.2.3 量測結果……………………………………………53
3.3冷卻水塔隔音牆量測………………………………………53
3.3.1 隔音牆材料之選擇………………………………53
3.3.2 量測儀器……………………………………………54
3.3.3 隔音鋁牆及各類AP板之架設……………………55
3.3.4 實驗量測設定及步驟……………………………58

第四章 實驗結果與討論………………………………………76
4.1背景因素……………………………………………………76
4.1.1環境氣候因素………………………………………76
4.1.2背景噪音量測………………………………………77
4.2冷卻水塔之隔音牆研究……………………………………77
4.2.1 冷卻水塔之噪音量測結果………………………77
4.2.2 架設鋁隔音牆之噪音量測結果…………………78
4.2.3 鋁隔音牆上附加各類AP板……………………80
4.2.3.1 鋁隔音牆上層上半面附加單層AP板……80
4.2.3.2鋁隔音牆上層上半面附加雙層AP板……80
4.2.3.3鋁隔音牆上層全面附加單層AP板………81
4.2.4鋁隔音牆上附加各類吸音棉板…………………82
4.2.5 鋁隔音牆上層全面附加複合板…………………83
4.2.6 T形隔音牆…………………………………………84
4.3討論……………………………………………………85

第五章 結論…………………………………………………………107

參考文獻………………………………………………………………109

附錄A：實驗期間之風速量測表……………………………………111

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