Flame spreading over a liquid fuel floating on water stream

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H03924
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thermal engineering
• Research Institution: Hirosaki University
• Principal Investigator: ITO Akihiko 弘前大学, 理工学研究科, 客員研究員 (30127972)
• Co-Investigator(Kenkyū-buntansha): 鳥飼 宏之 弘前大学, 理工学研究科, 准教授 (50431432)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 津波火災 / 燃え拡がり / 液体燃料 / 対向流燃え拡がり / 並行流燃え拡がり / 拡散火炎 / マランゴニ対流 / 燃え拡がり速度

Outline of Final Research Achievements

In order to clarify the flame spreading mechanism of Tsunami fires, the combustion phenomena formed over a liquid fuel have been investigated experimentally. Two different kinds of flame spreading experiments were performed. One was the flame spreading formed over a liquid floating on a still water layer. The other was the opposed-flow flame spreading formed over a liquid fuel stream. As a result, it is seen that the spreading rate of the flame formed over still fuel and water layers becomes lower than that of the flame formed over a fuel layer. On the other hand, it is found that the spreading rate of the flame formed over the opposed fuel flow increases as the opposed fuel flow speed becomes larger. However, when the fuel flow speed is much larger than the flame spreading rate, the flame was flowed downstream.

Free Research Field

火災燃焼工学

Academic Significance and Societal Importance of the Research Achievements

東日本大震災で観察された津波火災という流れる海水上に浮いた液体燃料表面上の燃え拡がり現象について，従来の液体燃料上の燃え拡がりの知見をふまえて実験的にそして詳細に調べた．その結果，水に浮いている燃料の上に形成される火炎の方が，燃料層のみの上に形成された火炎よりも燃え拡がる速度が小さいことが分かった．これは，水の層が火炎の燃え拡がりを抑制することを意味している．また，対向する液体燃料流上に形成された火炎の燃え拡がり速度は，液体燃料流速の増加と伴に燃え拡がり速度が大きくなることが分かった．これは，火炎に対して水流の向きが燃え拡がり速度の増減を決定づけることを意味している．