本研究之目的在於以不同渦流溢放頻率計算方法分析自行開發之T型渦流流量計的量測不確定度，該渦流流量計原型，除採用傳統脈波累計方式求得累計流量並顯示於液晶螢幕LCD外，尚可提供弦波信號及方波信號輸出，該渦流流量計之性能分析結果將作為日後發展智慧型渦流流量計之依據。
本實驗中所測試之渦流流量計包含氣體渦流流量計及液體渦流流量計，氣體渦流流量計乃使用成大航太中心流量實驗室標準流量系統進行測試，流速範圍為12.72m/sec～77.6m/sec；雷諾數Red為2.56 ×104　～1.562 ×105，分別以無因次頻率St及流量係數K進行流量計性能分析。在此系統中，氣體渦流流量計得到之信號以FFT (Fast Fourier Transform method) 計算渦流溢放頻率，結果顯示最佳總擴充不確定度為±0.745﹪，最佳線性度為±1.777﹪。而以流量係數K進行性能分析，其總擴充不確定為±0.568﹪，線性度為±1.89﹪。
液體渦流流量計則於成大航太系之完全發展管流系統進行測試，測試流速範圍為0.446～4.5m/sec；雷諾數Red為5.6 ×103～5.29 ×104，以無因次頻率St進行流量計性能分析。液體渦流流量計使用FFT計算法及自相關性演算法(Autocorrelation method)等兩種計算渦流溢放頻率，經測試後建議雷諾數Red大於1.69×104使用FFT計算法﹔反之則使用自相關性演算法，所得總擴充不確定度為±0.802﹪﹔線性度為±0.391﹪。
上述液體渦流流量計之測試結果乃針對T型鈍型體的延長平板(splitter plates)為2d的情況，若將延長平板由2d改為1.56d裝置於液體渦流流量計測試，總擴充不確定度自±0.802﹪降低為±0.376﹪﹔線性度則由±0.391﹪增加為±0.963﹪，說明延長平板長度會影響總擴充不確定度及線性度。
該液體渦流流量計之累計流量誤差測試分別在3個流速下進行測試，其中渦流流量計之渦流產生器的延長平板長度為2d，結果顯示當累計流量於50m3以上，則於測試流速範圍內其器差為±0.2﹪。

In the present study, two T-shaped vortex flowmeters fabricated in laboratory were employed for testing in a gas flow calibration facility and a water pipe flow, respectively. The main purpose was to obtain the uncertainty of the vortex flowmeter in pipe flow measurement. In order to reduce the vortex shedding frequency from the signal obtained, the techniques of FFT and autocorrelation were employed. The calibration curve of St-Red and its corresponding uncertainty were then calculated. On the other hand, the calibration curve of K-Red was also obtained in this study, where K is denoted as the meter factor.
A gas vortex flowneter were calibrated using a standard flow measurement system in the Flow Measurement Laboratory, ASTRC NCKU. The velocity range calibrated is from 12.72 to 77.6m/sec, equivalent to a Reynolds number range of 2.56×104 ~ 1.56×105. By using FFT to reduce the vortex frequency, the uncertainty associated with the St-Red curve is ±0.745% and the linearity of the curve is ±1.777%. On the other hand, the uncertainty associated with the K-Red curve obtained is ±0.568﹪and the linearity is ±1.89%.
A liquid vortex flowneter was tested in a fully developed pipe flow system in the Department of Aeronautics and Astronautics, NCKU. The velocity range is from 0.446 to 4.5m/sec, equivalent to a Reynolds number range of 5.6×103 ~ 5.29×104. By combining the techniques of FFT and autocorrelation to calculate the vortex frequency, the uncertainty associated with the St-Red curve reduced is ±0.802% and the linearity of the curve is ±0.391%.
The T-shaped vortex flowmeters mentioned above have a splitter plate of length equal to 2d. By changing the length of the plate from 2d to 1.56d, the uncertainty of the St-Red curve obtained in the water pipe flow facility is ±0.376% and the linearity is ±0.963%, indicating that the length of the splitter plate affects the total uncertainty and the linearity.

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