2005 Fiscal Year Final Research Report Summary
Optical diagnostics of nanosecond and nanometer ignition and quenching
| Project/Area Number |
16360105
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Okayama University |
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Principal Investigator |
TOMITA Eiji Okayama University, Graduate School of Natural Science & Technology, Professor, 大学院・自然科学研究科, 教授 (80155556)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAHARA Nobuyuki Okayama University, Graduate School of Natural Science & Technology, Assistant Professor, 大学院・自然科学研究科, 助教授 (30314652)
IKEDA Yuji Okayama University, Imagineering, Inc., President(Researcher), 代表取締役(研究職) (10212789)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Laser ignition / Laser-induced plasma / Spectroscopy / Laminar premixed flame / Emission spectra |
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| Research Abstract |
In order to obtain basic data for analysis of ignition mechanism, chemiluminescence was measured at the flame front and the anchor point of laminar premixed CH_4/air and C_3H_8/air flames. Using the chemiluminescence spectra, anchor point location, local equivalence ratio, and flame temperature were examined. The local equivalence ratio was measured using the intensity ratio of OH^* and CH^* and the temperature were using measured the intensity ratio of the P and the R branches of the OH^* spectra. The local equivalence ratio and the temperature were lower near the anchor point.
When a powerful pulsed laser is focused to a small spot in gas, breakdown phenomena occurs and a spark plasma of high temperature and high pressure is created. If the laser beam interacts with a combustible gas, the plasma can ignite the gas. The emission spectra of the plasma were obtained by ICCD spectrometer and were captured using Framing ICCD camera. From these results, the following conclusions are obtained. (1)The shape of plasma turns out to be cylindrical at first. After that, the plasma expands spherically. The plasma size increases until 2000ns, after that time it was decreases rapidly. (2)The continuum spectrum by the bremsstrahlug and the recombination radiation came up at the earliest stage of the plasma development. Then the continuum spectrum decreased, the ionic spectra and the atomic spectra of hydrogen, nitrogen, oxygen, and carbon observed. (3)The plasma size was a correlated with the incident laser energy. The intensity ratios of H/O and H/N were found to be a liner function of equivalence ratio of the mixture. These results demonstrated that LIBS application can measure the local equivalence ratio of methane or propane premixed laminar flame.
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Research Products
(12 results)
