2023 Fiscal Year Final Research Report
Study on cool-flame spread using microgravity conditions for reconsideration of flame holding mechanism
| Project/Area Number |
19K04843
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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 24010:Aerospace engineering-related
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| Research Institution | Nihon University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
田辺 光昭 日本大学, 理工学部, 教授 (90291707)
菅沼 祐介 日本大学, 生産工学部, 准教授 (60739035)
齊藤 允教 日本大学, 理工学部, 准教授 (20801020)
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | 噴霧燃焼 / 冷炎 / 燃え広がり / 燃料液滴列 / 予蒸発予混合燃焼器 / 微小重力環境 |
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| Outline of Final Research Achievements |
Cool-flame spread along a decane droplet array was observed successfully under microgravity conditions and its spread speed was measured. The time when the slope of squared droplet diameter history changes remarkably was defined as the time when a cool flame reached the measured droplet. The cool flame spread speed was measured from the relationship between the droplet ignition time and the droplet positions for the second to sixth droplets. In the case that the initial droplet diameter and the droplet spacing were 0.75 mm and 2 mm respectively, the cool flame spread speed was 17.9 mm/s. The cool flame spread speed of the droplet spacing of 4 mm was larger than that of 2 mm. Cool flame spread along a decane droplet array of the initial diameter of 1 mm was numerically simulated successfully.
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| Free Research Field |
航空宇宙工学
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| Academic Significance and Societal Importance of the Research Achievements |
燃料液滴列の冷炎燃え広がりに着目し，噴霧を単純化した燃料液滴列を対象に基礎的な研究を行った．軸対称な火炎燃え広がりが実現される微小重力環境を利用した実験を行うことで，数値シミュレーションの検証を容易にした．冷炎点火温度を下回る温度の雰囲気において，強制点火装置により点火した冷炎が燃料液滴列を燃え広がる現象を初めて明らかにした．また，その現象を数値シミュレーションでも実現させた．予蒸発管の作動条件で冷炎燃え広がりが起こるのか否かなど，噴霧燃焼器で冷炎点火・燃え広がりが起こる条件を明らかにすることにより，その後に発生する熱炎の挙動を現在より正しく予測できるようになると考える．
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