| Project/Area Number |
02650184
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械力学・制御工学
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| Research Institution | Ashiya University (1991)
Osaka University (1990) |
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Principal Investigator |
NAKATANI Noboru Ashiya University, Faculty of Education, Professor, 教育学部, 教授 (10029085)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Photothermal effect / laser velocimetry / temperature measurement / heterodyne interferometer / multiple beam interferometer / 能動型繰り返し反射干渉計 / 光ファイバ・ヘテロダイン干渉計 |
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| Research Abstract |
The laser Doppler velocimeter (LDV), which has some advantages such as non-perturbing quality, capability of remote operation and high spatial resolution, has been well developed to measure flow velocity. However, the LDV needs scattering particles in flow. Recently, to be freed from this problem, velocimeter using photothermal effect have been investigated. Phase gradient variation induced by photothermal effect is measured by detecting phase deflection angle of probe laser beam using a position sensitive device. So accuracy of phase measurement is not good.
In this study we investigated on measurements of flow velocity and temperature. An optical fiber heterodyne interferometer and a multiple beam interferometer were developed for increasing sensitivity of phase detection. The former is free from external disturbances in the optical paths of the fibers and in the interferometer arms to measure small phase variation. The phase fluctuations due to external distrubances are excluded by differentiating the phase variations at two points in a flow field. The response time of the interferometer is 0.1 ms. The latter interferometer is very highly sensitive. The operating point is set on the maximum inclination of fringe intensity curve by the use of PZT tansducer or by controling injection current of a laser diode as a light source. The response time of the interferometer is 10 ns. Propagation time of laser photoacoustic pulse is detected with a multiple interferometer for measuring temperature. Displacement of phase variation due to photothermal effect is measured by the use of the heterodyne interferometer or the multiple beam interferometer. This photothermal method for measurement of temperqature is indepedent on quenching effect and is superior to laser induced method.
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