Two-Focused Optical Measurement Method of Flow velocity with Low-Coherent Laser Source

低相干激光源双焦点流速光学测量方法

• 批准号: 09650197
• 负责人: TANAKA Kazuhiro
• 金额: $ 2.05万
• 依托单位: Kyushu Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650197/
• 关键词: Low coherence; Superluminescent diode; SLD; Optical fiber; Interference spectrum; Traverse measurement; LASER measurement; Fluid measurement; レーザ

(1) The theoretical analysis of scattering media signals has been performed. According to this theory ;The flow velocity can be calibrated by using of the half peak value in the spectral width which is obtained by Fourier processing the interference output signals.This half peak value of spectral width is calculated without any relation to number density of scattering media.(2) By using the biological tissues(intralipid 1O%) as scattering media, the reproducible results can be obtained.(3) The interference output includes not only the fluctuation of scattering amplitude but noise signals. By subtracting noise signals from output signals, the useful fluctuation of scattering amplitude can be selected.(4) As the measurement point becomes deeper along a depth in a flow passage, the Fourier spectra of scattering amplitude gets smaller under the influence of the multiple scattering. Using intralipid 1O% as scattering media this tendency is the same.(5) The existence of wall can be recognized by the results of signal processing.(6) Near the wall surface, the positional resolution is about 40 mu m.(7) The spectral width measured at the chosen depths in the flow passage corresponds to flow velocity.(8) From the theory and simulation, it was clarified that the spectral signals are biasd toward higher region of spectral distribution by the velocity components differences of scattering particles passing through the measurement volume and by the time coherence function.(9) The effect of velocity gradient in measurement volume was analyzed quantitavely by using simulation and experemental results.

(1)对散射介质信号进行了理论分析。根据这一理论;通过对干涉输出信号进行傅里叶处理，得到谱宽的半峰值，利用该半峰值可以标定流速，该半峰值的计算与散射介质的数密度无关。(2)用生物组织（内含物10%）作散射介质，可获得重复性好的结果。(3)干涉输出不仅包括散射振幅的起伏，而且还包括噪声信号。通过从输出信号中减去噪声信号，可以选择有用的散射振幅起伏。(4)在多次散射的影响下，随着测量点沿流道深度沿着变深，散射振幅的傅立叶谱变小。使用10%的内禀素作为散射介质，这种趋势是相同的。(5)通过信号处理的结果可以识别壁的存在。(6)在壁面附近，位置分辨率约为40 μ m。(7)在流动通道中的选定深度处测量的光谱宽度对应于流速。(8)从理论和仿真结果可以看出，散射粒子通过测量体的速度分量差异和时间相干函数使光谱信号偏向光谱分布的较高区域。(9)利用仿真和实验结果定量分析了测量体积内速度梯度的影响。

项目成果

Kazuhiro Tanaka, Yoh Imai, Hiroshi Higo and Hiroki Tanaka: "New Measurement technique for Velocity Distribution with Optical Low-Coherent laser Source." Proc. of 5th Triennial Int. Symp. on Fluid Control, Measurement and Visualization, FLUCOME97. Vol. 1.

Kazuhiro Tanaka、Yoh Imai、Hiroshi Higo 和 Hiroki Tanaka：“利用光学低相干激光源测量速度分布的新技术。”

濱崎政之,長岡加奈子,肥後寛,田中和博: "低干渉光源を用いた光ファイバ型流動計測システムの評価" 日本機械学会九州学生会第29回卒業研究発表講演会論文集. 73-74 (1998)

Masayuki Hamasaki、Kanako Nagaoka、Hiroshi Higo、Kazuhiro Tanaka：《使用低干扰光源的光纤式流量测量系统的评估》日本机械工程学会九州学生会第 29 届毕业研究发表会论文集。 73-74 (1998)

濱嶋政之,田中和博: "低干渉光源を用いた光ファイバ型流動計測システムの評価" 日本機械学会九州学生会卒研発表講演会論文集. 第29回. 73-74 (1998)

Masayuki Hamashima、Kazuhiro Tanaka：“使用低干扰光源的光纤流量测量系统的评估”日本机械工程师学会九州学生协会毕业研究会议论文集第 73-74 期（1998 年）。

Kanako Nagaoka, Kazuhiro Tanaka, Yoh Imai: "Velocity Distribution Measurement Using Optical Low Coherent Source." Proc.of 4th KSME-JSME Fluids Eng.Conf.517-520 (1998)

Kanako Nagaoka、Kazuhiro Tanaka、Yoh Imai：“使用光学低相干源进行速度分布测量。”

K.Nagaoka,K.Tanaka,Y.Imai: "Velocity Distribution Measurement Using Optical Low Coherent Source" Proc.of 4th KSME-JSME Fluids Eng.Conf.517-520 (1998)

K.Nagaoka、K.Tanaka、Y.Imai：“使用光学低相干源进行速度分布测量”Proc.of 4th KSME-JSME Fluids Eng.Conf.517-520 (1998)