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標題: | 超音波感測技術應用於尿素溶液之濃度量測 Ultrasonic Concentration Measurement for Urea Solution |
作者: | Chih-Kai Huang 黃智楷 |
指導教授: | 宋家驥(Chia-Chi Sung) |
關鍵字: | 超音波,尿素,濃度,聲速,衰減,超音波換能器, Ultrasonic,Urea solution,Concentration,Ultrasonic velocity,Power attenuation,Ultrasonic transducer, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 近年來環境保護的觀念日趨普及,空氣污染的議題也不斷地被重視,為了將柴油引擎車所排放的有害廢氣轉化為無害物質,目前市面上普遍使用由尿素配置的觸媒還原劑進行轉換,而此觸媒劑的濃度品質將影響其轉換效率,因此即時監控最佳尿素濃度以確保反應效率就變成非常重要。本研究欲以超音波感測技術作為尿素溶液之濃度監測機制,希望利用自製高頻超音波換能器進行尿素濃度量測,透過實際量測不同濃度之尿素溶液下的超音波特性,將相關特性數值化並建立與濃度之經驗率定曲線。
本研究透過自製三種頻率的超音波換能器進行量測,採用回波法之擷取方式,針對超音波於尿素溶液中的傳遞速度以及能量衰減進行分析。研究結果顯示,超音波於尿素溶液中之傳遞速度與其濃度具有相當高的線性相關,利用本研究之超音波聲速量測架構進行濃度量測,三種頻率的結果中兩者的線性回歸式判定係數皆達0.999以上,並討論了本量測方法之精確度及不同溫度條件下的量測結果,最後建立一濃度-溫度-聲速之轉換關係式。透過相同量測架構,也利用超音波於尿素溶液中的能量衰減進行感測,研究結果發現,能量衰減係數與尿素濃度之相關性較低,不適合用於尿素溶液的感測。 Global warming and air pollution have become an issue of common international concern. For the purpose of converting harmful exhaust gases emitted by diesel engine vehicles into harmless substances, it is necessary to add a catalyst reduction which consists of certain proportions of urea and deionized water, and it is important to monitor the urea concentration in real-time to maintain the high reaction efficiency. Therefore the aim of this study attempted to measure the urea concentration by the self-made high-frequency ultrasonic transducer and to measure the ultrasonic properties of different concentrations of urea solution by echo method to find the correlation between concentration and propagation speed/power attenuation. The results showed that the concentration measurement using the high-frequency ultrasonic measurement system of this study could achieve a very high linear correlation between the propagation velocity and urea concentration. Due to the results, it could further build a conversion formula of concentration-temperature-sound velocity and achieving high-resolution, high-accuracy concentration measurement requirements. As for the power attenuation part, the results showed that it was not suitable for the measurement of urea concentration due to the low correlation between attenuation coefficients and the urea concentration |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74264 |
DOI: | 10.6342/NTU201903281 |
全文授權: | 有償授權 |
顯示於系所單位: | 工程科學及海洋工程學系 |
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