- 學位論文
應用皮托管原理設計分析新型流量計
Design and Analysis for a New-type Flowmeter Based on Pitot-tube Principle
摘要
本研究首先以CAD軟體進行量測方式的雛型設計，在大口徑水管內裝置靜壓管與全壓管用以量取壓差，並應用皮托管原理獲取水管內局部位置的流速，此方面量測模擬是藉由CFD技術來完成。數值實驗參數包括計算網格分布、不同入口之測試速度、靜壓管之入口位置、全壓管之入口位置等。獲得水管截面之局部位置的模擬速度後，本研究借助數值積分技術將所量得的流速與截面積結合運算，以求取量測剖面的流量，並藉此估算模擬結果與理論流量的相對偏差。另外實驗用流量計已至TAF認可實驗室進行數據量測，與標準水量計實驗之偏差分別為：流量為100 m3/hr之相對偏差是8.9%；流量為200 m3/hr之相對偏差是-2.63%；流量為300 m3/hr之相對偏差是-6.27%，預期本研究所設計的實驗用流量計經進一步改良後，將可實際應用於大口徑水管的現場校驗之用。
並列摘要
In this study, conducted prototype design of this measurement device by CAD software. A set of static tube and the total pressure tubes was installed to take the pressure difference in the pipe, and the principle of Pitot tube was applied to obtain local flow velocity. The CFD techniques has been used to simulate the measuring process. Numerical parameters included mesh distribution, various inlet velocity, the location of static tube and the location of total-pressure tube. We employ numerical integration for acquiring flow rate from multiplying velocity with cross section. Therefore, relative errors can be obtained by comparing simulated data and theory. Besides, the flowmeter for experiment has been tested in a laboratory credited by TAF. The relative errors as measured data compared with standard method for flowmeter are 8.9% for 100 m3/hr, -2.63% for 200 m3/hr and -6.27% for 300 m3/hr. It is anticipated that the flowmeter being improved to be a commercial product is very possible.