Elucidation of Controlloing Factors of Spontaneous Ignition of Fuel Droplet Cloud

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03899
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Kyushu University
• Principal Investigator: Moriue Osamu 九州大学, 工学研究院, 教授 (70363124)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 燃焼 / 噴霧 / 自着火

Outline of Final Research Achievements

A fundamental study on spontaneous ignition of fuel spray in hot ambient gas was carried out. Ignition behavior of an isolated fine fuel droplet whose diameter is about dozens of microns was experimentally and numerically studied. Evaporation rates obtained by the experiments were almost comparable with those of numerical analysis, while ignition delays of cool flame were not comparable. Ignition behavior of a fuel droplet pair was also experimentally and numerically studied. In most conditions cool flame appears from the outside of the pair. However, in several conditions cool flame appears between the droplets. The behavior above was explained by numerical analysis considering Damkoehler number as one of controlling factors.

Free Research Field

燃焼工学

Academic Significance and Societal Importance of the Research Achievements

単一微小液滴について，冷炎の自着火遅れに実験と数値解析で隔たりが見られたが，特に逆火や過早着火を予測する数値解析においては，冷炎発生限界近傍における化学反応モデルの信頼性の改良が要されることが示唆される．冷炎を発生する低温酸化反応は温度依存性が高く，粗大二液滴の実験においては，従来二液滴の外側の高温部でのみ冷炎が発生することが確認されていたが，数値計算上初期液滴径を減少させると液滴間で冷炎が発生し得ることが確認された．反応場の局所的な温度，濃度の履歴が自着火の有無，場所を支配する因子として扱われてきたが，局所ダムケラ―数も支配因子として重要であることを示している．