2004 Fiscal Year Final Research Report Summary
SCIENTIFIC ANALYSIS OF DUST EXPLOSION PHENOMENA
| Project/Area Number |
14580473
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
社会システム工学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
DOBASHI Tistu The University of Tokyo, Graduate School of Engineering, Associate Professor, 大学院・工学系研究科, 助教授 (30237177)
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| Project Period (FY) |
2002 – 2004
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| Keywords | DUST EXPLOSION / COMBUSTIBLE POWDER / IGNITION / FLAME PROPAGATION / SAFETY / DIAMETER DISTRIBUTION / HIGH SPEED PHOTOGRAPH |
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| Research Abstract |
The potential hazard of dust explosion is increasing due to the recent development of advanced technology. The prevention technique of dust explosions must be changed from the present "field test style" to systematic method of scientific base to manage the explosion risk in the advanced technologies. In this study, the scientific analysis of flame propagating phenomena during dust explosion was conducted to make clear the dust explosion phenomena scientifically. The following results were drawn.
1.The experimental apparatus and procedure were established, which is suitable to analyze the flame propagating phenomena during dust explosion. The combustible dust is formed by spraying liquefied heated solid fuel. It is easy to control the particle size distribution and concentration by changing the spraying condition.
2.It was found in the observation of propagating flame by high speed photographs that the leading edge of the dust flame is propagating not discretely but continuously.
3.The starting point of combustion reaction was analyzed by the observation of chemical luminescence (OH emission and CH emission). It was found that the combustion reaction starts at the point a few mm ahead of the visible leading edge of the flame.
4.It was found that the flammable limit strongly depends on the number density of small particles. This result suggests that the combustion reaction at the leading edge of the flame is supported by the combustion of small particles.
5.The analysis of above mentioned results from the viewpoints of heat transfer, vaporization, and mass transfer were made to establish a theoretical model of the dust flame propagation.
These results are useful not only in the sense of safety engineering (prevention of dust explosion accidents), but also in the academic sense (combustion research).
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