2021 Fiscal Year Final Research Report
Laser solid target interaction induced ignition phenomenon of fuel-air premixture
| Project/Area Number |
19K04250
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 19020:Thermal engineering-related
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| Research Institution | Nihon University (2021)
National Institute of Advanced Industrial Science and Technology (2019-2020) |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 着火 / レーザーブレイクダウン / アブレーション / 誘起流動 |
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| Outline of Final Research Achievements |
It has been known that when pulsed laser is focused near the surface of a solid target in the fuel-air premixture can be ignited with significantly lower energy than when it is focused in a gas, but the mechanism is not well understood. In this study, in order to clarify this, the effects of the laser focusing point and target spacing, and the target surface and laser incident angle on ignition were examined. The irradiation energy density was evaluaed by observing the focused laser beam profile, and the initial flame kernel was visualized by schlieren measurement. As a result, it was clarified that the ignition is a complex phenomenon of the fluid motion induced by the laser breakdown plasma and the ablation of the target material.
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| Free Research Field |
燃焼工学
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| Academic Significance and Societal Importance of the Research Achievements |
内燃機関の着火方法を従来の方法から，レーザーを用いる着火にすることによって，希薄，且つ高圧な混合気の着火を可能とすることで熱効率を高め，CO2排出量を削減することができる．本研究によって，その着火に必要なレーザーエネルギーを抑制する方法や条件が明らかになったことから，レーザーによる多点着火などの新たな燃焼方法の可能性への展開が期待できる．また，近年の高エネルギー放電を希薄混合気への着火に用いる取り組みにおいても，電極に短時間にエネルギーが付与される状況は本研究で検証した条件と近く，電極材料のアブレーション効果は今後の着火研究に対して重要な知見を与える．
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