臺灣博碩士論文加值系統

本研究提出一光纖光柵流速計，其主要感測元件為兩根中心波長近乎相等且有些微不同反射率之布拉格光纖光柵(FBGs)，經過特殊封裝設計，將兩根光柵封裝於一金屬圓柱體內，感測其金屬圓柱體內之壓力差。光纖光柵壓力差感測器結合文氏管(Venturi meter)或孔口計(Orifice meter)完成光纖光柵流速計。
光纖光柵流速計運作原理是當流體流經文氏管與孔口計時，藉由對其兩壓力出口之壓力差的感測值轉換為光纖光柵中心波長的變化，由光纖光柵流速計中光纖光柵中心波長位置，可獲得管中流體流速、流量，且由光纖光柵流速計之幾何尺寸調整可變改此種機制的感測靈敏度。未來期望能將此感測器實際運用於油管路和自來水管路作有效監控。

The velocimeter based on fiber gratings is proposed in this study and its main sensing elements are two fiber Bragg gratings with same central wavelength and a little bit different reflectivities. By using a special packaged-structure in which the two fiber Bragg gratings are packaged in a metal cylinder for sensing a differential pressure. The velocimeter is composed of this differential pressure sensor, an Venturi meter or an orifice meter.
The mechanism of the velocimeter is that the differential pressure resulted from a fluid flowing through Venturi meter or orifice meter causes the variation of the central wavelength of fiber Bragg gratings. The flow and flowing velocity of the fluid in the tube can be calculated by the differential pressure obtained from two ports of an Venturi meter or an orifice meter. The measuring sensitivity is proportional to the dimension of the sensor. Thus the variation of the central wavelength of fiber Bragg gratings can be used for monitoring the flowing velocity of fluid in real time. In the future, we expect that the velocimeter can be applied in monitoring oil pipeline and water pipeline practically.

摘 要 I
ABSTRACT II
誌 謝 III
目 錄 IV
圖目錄 VII
表目錄 XI
第一章 緒 論 1
1.1 研究動機 1
1.2 研究目的 1
1.3 研究方法及本文架構 2
第二章 光纖之光學特性 4
2.1 光纖基本架構 4
2.2 光纖光柵簡介 8
2.3 光纖光柵之物理特性與理論分析 11
2.3.1 布拉格光纖光柵 11
2.3.2 布拉格光纖光柵理論分析 12
2.4 光纖光柵寫製方法[20] 16
第三章 管路流量計量測原理 21
3.1 前言 21
3.2管路流量計實驗裝置簡介 21
3.3 文氏管及孔口計計算流量原理 23
3.4 管路流量計實驗步驟及結果 25
第四章 光纖光柵流速計的設計與原理 32
4.1 前言 32
4.2 壓力差感測器簡介 32
4.2.1 壓力差感測器之構造[10] 32
4.2.2 壓力差感測器原理與實驗結果分析[10] 33
4.2.3 實驗用壓力差感測器的製作 37
4.3 光纖光柵流速計的構造與原理 38
第五章 實驗與分析 41
5.1 壓力差感測器量測 41
5.1.1 實驗架設 41
5.1.2 實驗結果與分析 42
5.2 壓差感測器結合文氏管之光纖光柵流速計流速量測 47
5.2.1 實驗架構 47
5.2.2 實驗結果與分析 49
5.3 壓差感測器結合孔口計之光纖光柵流速計流速量測 57
5.3.1 實驗架構 57
5.3.2 實驗結果與分析 59
5.4 小結 65
第六章 結論與未來展望 67
參考文獻 69

[1]Y. Zhao, Y. Zhao, M. Zhao, “Novel force sensor based on a couple of fiber Bragg gratings,” J. Measurement, Vol.38, pp.30-33, 2005.
[2]H. L. Liu, H. Y. Tam, C. Y. Lo, S. W. Or, “A novel high frequency magnetostrictive composite-fiber Bragg grating sensor,” Osa. Ofc, pp.1-3, 2007.
[3]Y. Zhao, Q. Meng, K. Chen, “Novel current measurement method based on fiber Bragg grating sensor technology,” Sensors and Actuators, Vol.126, pp.112-116, 2006.
[4]Y. P. Wang, W. Jin, D. N. Wang, “Unique temperature sensing characteristics of CO2-laser-notched long-period fiber gratings,” Optics and Lasers in Engineering, Vol.47, pp.1044-1048, 2009.
[5]C. L. Tien, C. C. Hwang, H. W. Chen, W. F. Liu, S. W. Lin, “Magnetic Sensor Based on Side-Polished Fiber Bragg Grating Coated with Iron Film,” IEEE tranctions on magneticss, Vol.42, pp.3285-3287, 2006.
[6]F.J.Arregui,I. R. Matias, K. L. Cooper, R. O. Claus, “Simultaneous Measurement of Humidity and Temperature by Combining a Reflective Intensity-Based Optical Fiber Sensor and a Fiber Bragg Grating,” IEEE Sensors Journal, Vol.2, No.5, pp.482-487, 2002.
[7]Z. C. Zhuo, B. S. Hama, “A temperature-insensitive strain sensor using a fiber Bragg grating,” Optical Fiber Technology, Vol.15, pp.442-444, 2009.
[8]T. Guo, Q. Zhao, Q. Dou, H. Zhang, L. Xue, G. Huang, and X. Dong, “Temperature-insensitive fiber Bragg grating liquid-level sensor based on bending cantilever beam,” Photon Tech, Lett.17, pp.2400-2402, 2005.
[9]K. Fukuchi, S. Kojima, Y. Hishida, and S. Ishi, “Optical water-level sensors using fiber Bragg grating technology,” Hitach Cable, Rev.21, 23-28, 2002.
[10]H. J. Sheng, W. F. Liu, K. R. Lin, S. S. Bor, and M. Y. Fu, “High-sensitivity temperature-independent differential pressure sensor using fiber Bragg gratings,” Optics Express, Vol.16, pp.16013-16018, 2008.
[11]Y. Zhao, C. Yub, and Y. Liao, “Differential FBG sensor for temperature-compensated high-pressure (or displacement) measurement,” J. Opt. Laser Techno, Vol. 36, pp.39-42, 2004.
[12]J. Lim, Q. P. Yang, B. E. Jones, and P. R. Jackson, “DP flow sensor using optical fiber Bragg grating” J. Sensors and Actuators, Vol.92, pp.102-108, 2001.
[13]Y. Zhang, D. Feng, Z. Liu, Z. Guo, X. Dong, K. S. Chiang, and B. C. B. Chu, “High-sensitivity pressure sensor using a shielded polymer-coated fiber grating,” IEEE Photon. Technol. Lett.13, 618-619, 2001.
[14]Y. Liu, Z. Guo, Y. Zhang, K. S. Chiang, and X. Dong, “Simultaneous pressure and temperature measurement with polymer-coated fiber Bragg grating,” Electron. Lett.36, pp.564-566, 2000.
[15]S. C. Chen, D. Y. Wang, and S. C. Yen, “Application of Acoustic Doppler Velocimeter in Flume Experiments,” Journal of Soil and Water Conservation, Vol.32(2), pp.133-143, 2007.
[16]J. Hecht, Understanding Fiber Optics, Chapter 2, pp.17-29, 2006.
[17]K. O. Hill, Y. Fujii, D. C. Johnson, and B. S. Kawasaki, “Photosensitivity in Optical Fiber Waveguides: Application to Reflection Filter fabrication,” Applied Physical Lett., Vol. 32, pp. 647-649, 1978.
[18]K. O. Hill, et al, “Fiber Bragg grating technology fundamentals and overview,” Journal of Lightwave Technology, Vol. 15, No. 8, pp. 1263-1276, 1997.
[19]T. Redogan, “Fiber Grating Spectra,” Journal of Lightwave Technology, Vol. 15, No. 8, pp. 1277-1294, August 1997.
[20]A. D. Kersey, et al., “Fiber Grating Sensors,” Journal of Lightwave Technology, Vol. 15, No. 8, pp. 1442-1463, August 1997.
[21]D. F. Young, B. R. Munson, and T. H. Okiishi, A Brief Information to Fluid Mechanics, Chapter 8, Viscous flow in pipes, pp.363-367, 1997.
[22]D. Halliday, R. Resnick, J. Walker, Fundamentals of Physics, Chapter 14, pp.14.16-14.20, 2005.