Analysis on bursting mechanism of carbon steel sparks
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- Kimura Taro
- Department of Aeronautics and Astronautics, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
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- Inoue Chihiro
- Department of Aeronautics and Astronautics, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
説明
A metal spark generated by grinding carbon steel has been recognized proceeding multiple bursting events, akin to the luminous branching fireworks. The mechanism of successive fragmentation observed in carbon steel spark, however, has not been elucidated yet. In the present study, we develop a new comprehensive analytical framework for estimating the droplet size of carbon steel sparks, time of flight, and time-variant temperature, combined with high-speed images of the spreading sparks, for the quantitative discussion of the timescale of bursting metal sparks. We find that the flight time to burst for a mother droplet is independent of the content of carbon, corresponding to the Fourier number for the molecular diffusion of unity. The successive fragmentation of carbon steel sparks is rate-controlled by the molecular diffusion of ambient oxygen inside the droplet. Since the measured temperature indicates that the heat is produced by the oxidation of iron, the successive fragmentation stops when the iron in the spark is fully oxidized, immediately becoming a solid particle.
収録刊行物
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- Science and Technology of Energetic Materials
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Science and Technology of Energetic Materials 83 (3), 95-101, 2022
一般社団法人 火薬学会
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詳細情報 詳細情報について
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- CRID
- 1390011231104905472
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- ISSN
- 24346322
- 03685977
- 13479466
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- KAKEN
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- 抄録ライセンスフラグ
- 使用不可
