水管洩漏之聲訊量測與模擬研究

Study of Water Pipeline Leakage Induced Acoustic Signal

吳銘洲(MingChou Wu)

指導教授 ： 陳琪芳

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202100780

摘要

本研究分別使用有限元素法 (Finite Element Method, FEM) 及實驗進行，用以預估洩漏噪音音傳損耗及洩漏噪音特徵。第一部分則工業技術研究院量測技術發展中心所建立之室外管線迴路進行實驗。將量測環境噪音、背景噪音及洩漏噪音三者利用聲功率頻譜進行比較，找出洩漏噪音特徵，並開啟不同洩漏孔洞，用以計算水管線中之音傳損耗。第二部分則利用有限元素軟體進行計算，以建立聲振耦合模型 (acoustic-structure coupled) 在頻域中模擬，並加入不同材質、尺寸及結構接頭之模型，計算低頻點聲源於管內之音傳損耗，進而推測洩漏噪音於不同情形可傳播的距離。在實驗中發現，在2吋聚乙烯(PE)管管線中，在400 Hz至500 Hz頻帶中其音傳損耗為最小且能分辨出洩漏噪音的特徵，能夠傳遞最遠，可做為偵測洩漏之主要對象；在1吋不鏽鋼管管線中，洩漏噪音能量於管線中損耗不大，採用800 Hz至1000 Hz間頻帶訊號為主要偵測重點。模擬結果得知聚乙烯管線中能量損失皆較金屬管大，且洩漏噪音能量在經過不同結構接頭皆會大幅降低，。綜上所述，水管線洩漏特徵及洩漏噪音音傳損耗，將有助於建立地下水管線多點式相關儀設計之參考。

關鍵字

洩漏噪音 ； 有限元素法 ； 聲振耦合 ； 音傳損耗

並列摘要

This study was conducted in the usage of Finite Element Method (FEM) with experiments to estimate the acoustic transmission loss and characteristics of leakage noise. The first part was to convey experiments with the outdoor pipeline loop which composed by the Measurement Technology Development Center of Industrial Technology Research Institute. The measurement of environmental noise, background noise and leakage noise was juxtaposed with the sound power spectrum to ascertain the characteristics of leakage noise. Then, various leakage holes were opened to compute the sound transmission loss in the water pipeline. The second part deployed FEM software to perform calculations which established an acoustic-structure coupled model simulation in the frequency domain and collated models of different materials, sizes and structural joints upon low frequency. The transmission loss could speculate the travel distance under different situation. In the experiment, it was found that in the 2-inch polyethylene (PE) pipeline, the sound transmission loss is the smallest in the 400 Hz to 500 Hz frequency band, and the characteristics of leakage noise can be distinguished. It can transmit the farthest as a leak detection. In the 1-inch stainless steel pipe pipeline, the leakage noise energy is not large in the pipeline. The frequency band signal between 800 Hz and 1000 Hz is used as the main detection target. The results suggested that leakage noise energy would significantly diminish among plastic tube and different structural joints. In conclusion, the leakage characteristics of water pipelines and the sound transmission loss of leakage noise would infer a reference for the design of multi-point correlator of underground water pipeline.

並列關鍵字

leakage noise ； finite element method ； acoustic-structure coupled model ； transmission loss

參考文獻

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