基於超音波都卜勒原理之流速量測系統建構與信號分析

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Title:	基於超音波都卜勒原理之流速量測系統建構與信號分析
Authors:	林維盛;Lin, Wei-Sheng
Contributors:	機械工程學系
Keywords:	超音波;微粒;都卜勒效應
Date:	2025-12-26
Issue Date:	2026-03-06 19:01:27 (UTC+8)
Publisher:	國立中央大學
Abstract:	摘要本研究建立一套以超音波都卜勒為基礎之流速與濃度估測系統。實驗採用連續波進行量測，並模擬5 MHz壓電片（PZT）發射與接收端驅動電路，以分析匹配電感對頻率響應之影響。接收訊號透過示波器擷取後進行分析。流速估測方面，利用快速傅立葉轉換（FFT）估算流速，並進一步結合鎖相迴路（PLL）與希爾伯特-黃轉換（HHT）進行時間域流速分析，以作為比較與驗證。濃度估測方面，分別於頻域與時域中以散射訊號能量作為濃度指標進行分析。實驗架構採用壓克力腔體搭配矽膠管，並以幫浦調控流速以模擬不同流體狀態。實驗結果顯示，本系統能有效估測管道內流速與濃度變化，證明本研究方法於流速與濃度檢測的可行性。關鍵詞：超音波、微粒、都卜勒效應 ;ABSTRACT This study establishes a flow velocity and concentration estimation system based on the ultrasonic Doppler principle. Continuous-wave ultrasound was employed for measurements, and the 5 MHz piezoelectric (PZT) transmitter and receiver driver circuits were simulated to analyze the effect of matching inductance on the frequency response. The received signals were captured by an oscilloscope and processed. For flow velocity estimation, the Fast Fourier Transform (FFT) was applied, and further combined with a phase-locked loop (PLL) and the Hilbert–Huang transform (HHT) to perform time-domain flow velocity analysis for comparison and validation. For concentration estimation, the scattering signal energy was analyzed as the concentration indicator in both the frequency and time domains. The experimental setup employed an acrylic chamber with a silicone tube, and a pump was used to regulate the flow rate to simulate various fluid conditions. Experimental results demonstrate that the proposed system can effectively estimate flow velocity and concentration variations within the pipeline, confirming the feasibility of the proposed method for flow velocity and concentration measurement. Keywords: ultrasound, particles, Doppler effect
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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