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Develpment of Karman Vortex Velocimeter by Use of Laser Diode

激光二极管卡门涡街测速仪的研制

基本信息

批准号：
02650139
负责人：
SAITO Susumu
金额：
$ 1.15万
依托单位：
Science University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650139/
关键词：
Velocimeter Karman vortex Laser Diode Vortex flowmeter Pulsating flow F V converter 半導体レ-ザ-

项目摘要

A velocimeter which is applicable to gas and liquid flow was developed. The frequency of the Karman vortex downstream of a small diameter wire (0.3mm, 0.5mm and 1mm) set perpendicular to the flow is measured. The parallel light (diameter : 1mm) from a laser diode is refracted by the vortex and it is detected with a photo diode. The wire is heated by applying a low-voltage electrical charge in order to strengthen the refraction of light. The frequency is measured with FFT analyzer.The frequency of the Karman vortex and the velocity are almost linear. It was confirmed experimentally that the velocity range between 3m/s and 200m/s could be measured, and it is supposed that higher velocity is also avairable.Two methods were carried out to measure the velocity profile. One is a method which measures the frequency by scanning the laser light along the wire (vortex generator). The another is a method which measures the frequency by moving the wire.Almost same results between this method and Pitot tube were obtained as for the wire of a small diameter such as 0.3mm and 0.5mm. As the diameter became larger, the difference between the two measurements became higher. Beside, the wire of small diameter showed favorable results in a smoll disturbance of the flow, a fine wave form and a low electrical power consumption.A flowmeter for water flow in a small diameter pipe (diameter : 5mm) was also developed in a same way to the velocimeter. The wire of small diameter from 0.1mm to 0.5mm were used as the vortex generator. The relation between the flow rate and the frequency which is almost linear. F/V converter was also used successfully to measure the frequency. The converter was available to measure a sinusioidal flow rate up to 40Hz.

研制了一种适用于气体和液体流动的测速仪。测量了垂直于流动方向的直径较小的金属丝（0.3mm、0.5mm和1mm）下游的卡门涡频率。平行光（直径：1mm）从一个激光二极管被涡流折射，它被一个光电二极管检测。电线通过施加低压电荷来加热，以加强光的折射。用FFT分析仪测量频率。卡门涡的频率和速度几乎是线性的。实验证实，可以测量到3m/s ~ 200m/s的速度范围，并推测还可以获得更高的速度。采用两种方法测量速度剖面。一种是通过扫描激光沿导线（涡流发生器）测量频率的方法。另一种是通过移动导线来测量频率的方法。对于直径较小的丝，如0.3mm和0.5mm，这种方法与皮托管的结果几乎相同。随着直径变大，两种测量值之间的差异也越来越大。此外，小直径导线对气流扰动小，波形好，电耗低，具有良好的效果。在流速计的基础上，还研制了一种测量小直径管道（直径：5mm）水流的流量计。涡流发生器采用直径为0.1mm ~ 0.5mm的小线材。流量与频率之间的关系几乎是线性的。F/V变换器也被成功地用于测量频率。该转换器可用于测量高达40Hz的正弦流量。