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Mmltimode fiber optic laser Doppler anemometer with side-projected catheter

机译:Mmltimode fiber optic laser Doppler anemometer with side-projected catheter

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摘要

A new side-projected catheter for in vivo blood flow measurements has been developed and tested. This catheter is designed to measure blood flow in both the forward (towards the catheter tip) and reverse (away from the catheter tip) flow directions. It consists of two multimode optical fibres with core diameter of 50μm and cladding diameter of 125 μm. One fibre transmits the laser beam into blood and the other receives the back-scattered light from the erythrocytes within the probe volume. The experimental plots of the dominant frequency (frequency with the highest amplitude) against the flow velocity are found to be linear in both the forward and reverse flow directions. This result was reaffirmed by the numerical flow simulation along the fibre catheter side wall. In the simulation, it was found that the flow within the boundary layer is indeed laminar, and hence the relationship between the Doppler shift frequencies and the flow velocities is linear, thereby making the linear calibration possible for predicting the free stream flow velocity. The analysis of the experimental and the computational results indicated that the boundary layer along the side wall of the fibre catheter varies with both the flow velocity and flow direction. Furthermore, using the fibre optic catheter with an increasing fibre core separation, it was observed experimentally and numerically that the percentage of the free stream flow velocity increases, suggesting that the projection of the measuring probe volume is indeed moving towards the free stream domain.#1998 Society of Photo-Optical Instrumentation Engineers. S0091-3286(98)02106-0 Subject terms: Doppler frequency; boundary layer; laminar; free stream; an-emometry. Paper 44077 received July 23, 1997; revised manuscript received Jan. 29, 1998; accepted for publication Jan. 30, 1998.

著录项

  • 来源
    《Optical Engineering》 |1998年第6期|1677-1683|共7页
  • 作者单位

    Nanyang Technological University School of Electrical and Electronic Engineering/ Nanyang Avenue;

    Nanyang Technological University School of Electrical and Electronic Engineering /Nanyang Avenue;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 英语
  • 中图分类 光学仪器;
  • 关键词

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