Relationship between the existence of flow and explosion intensity in a dust explosion accident

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04573
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 25020:Safety engineering-related
• Research Institution: Gunma National College of Technology
• Principal Investigator: Hanai Hironao 群馬工業高等専門学校, 機械工学科, 准教授 (30312664)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 粉じん / 爆発 / 乱れ / 爆発強度

Outline of Final Research Achievements

We clarified the effect of turbulence present at the time of an explosion on intensity of explosion, which provides important insight into the analysis of dust explosion accidents caused by combustible powder. It was found that the effect of turbulence on explosion intensity varies depending on the size of the powder. In experiments using a closed vessel, it was found that the effect of turbulence on maximum pressure is greater when the dust concentration is low. On the other hand, it was found that the maximum pressure gradient is more affected by turbulence when the powder concentration is high. Regarding powder size, it was found that the effect of turbulence is greater for small powder. These effects could be explained by the change in convective heat transfer coefficient due to turbulence and the increase in flame surface area.

Free Research Field

燃焼学

Academic Significance and Societal Importance of the Research Achievements

本成果は，可燃性粉体が空間に散布されそれに適切な熱が加わった時に発生する粉じん爆発の原因分析における基礎データの提供を行った．粉じん爆発は，一般には起こり難い現象である．いくつかの条件が整わないと発生しない．多くの場合，流れにより適切な粉じん雲が形成され爆発環境を整える．ガス爆発に関しては，乱れが爆発特性に及ぼす影響については理解が進んでいる．しかし，粉じんに対しては，粉体の気化特性や形状，表面性状や気化温度など多くの因子が乱れの影響を受けるため，それらを説明し得る基礎データの提供が行われていなかった．本研究では，主に乱れと粉体濃度および粉体サイズに対する関連を主眼に原因の究明を行った．