Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Concentration profile of particles across a flame propagating through an iron particle cloud
Prevention of accidental dust explosions is an important subject for safety management in industrial processes in which combustible powders are handled. Once a dust explosion happens in the processes, serious harms often spread far and wide. It is difficult to appropriately prevent accidental dust explosions and suppress the damages without clear understanding of such basic phenomena of dust explosion as, how a flame is formed and how it propagates in a combustible dust cloud. The number density profile of particles across a flame propagating through an iron particle cloud has been examined experimentally. The iron particles were suspended in air and ignited by an electric spark. Measurements were performed using high-speed photomicrography combined with laser light scattering technique. For relatively large, agglomerated particles the number density of iron particles changes in the range of x smaller than 11.0 mm, where x is the distance from the leading edge of the combustion zone. The number density increases with the decrease of x in the range 0.6 smaller or equal x smaller or equal 11.0 mm, reaches a maximum at x about 0.6 mm, and then decreases. The maximum value of the number density is about 2.6 times larger than that at the region far ahead of the flame, x > 11.0 mm. This increase in the number density of particles must cause a change of the lower flammability limit. By assuming that the increase in the number density is caused by the velocity difference of particles from surrounding gas flow, the profile of the number density of particles has been estimated on the basis of measured velocities of particles. The estimated number density profile of particles agrees well with that of the measured profile. The increase in the number density of particles just ahead of the flame will appear not only in iron particle cloud but also in any two-phase combustion systems, such as combustible particle cloud, combustible spray and so on.
Concentration profile of particles across a flame propagating through an iron particle cloud
Prevention of accidental dust explosions is an important subject for safety management in industrial processes in which combustible powders are handled. Once a dust explosion happens in the processes, serious harms often spread far and wide. It is difficult to appropriately prevent accidental dust explosions and suppress the damages without clear understanding of such basic phenomena of dust explosion as, how a flame is formed and how it propagates in a combustible dust cloud. The number density profile of particles across a flame propagating through an iron particle cloud has been examined experimentally. The iron particles were suspended in air and ignited by an electric spark. Measurements were performed using high-speed photomicrography combined with laser light scattering technique. For relatively large, agglomerated particles the number density of iron particles changes in the range of x smaller than 11.0 mm, where x is the distance from the leading edge of the combustion zone. The number density increases with the decrease of x in the range 0.6 smaller or equal x smaller or equal 11.0 mm, reaches a maximum at x about 0.6 mm, and then decreases. The maximum value of the number density is about 2.6 times larger than that at the region far ahead of the flame, x > 11.0 mm. This increase in the number density of particles must cause a change of the lower flammability limit. By assuming that the increase in the number density is caused by the velocity difference of particles from surrounding gas flow, the profile of the number density of particles has been estimated on the basis of measured velocities of particles. The estimated number density profile of particles agrees well with that of the measured profile. The increase in the number density of particles just ahead of the flame will appear not only in iron particle cloud but also in any two-phase combustion systems, such as combustible particle cloud, combustible spray and so on.
Concentration profile of particles across a flame propagating through an iron particle cloud
Konzentrationsprofil von Partikeln über eine sich in einer Eisenpartikelwolke ausbreitenden Flamme
Sun, J. (Autor:in) / Dobashi, R. (Autor:in) / Hirano, T. (Autor:in)
Combustion and Flame ; 134 ; 381-387
2003
7 Seiten, 9 Bilder, 1 Tabelle, 23 Quellen
Aufsatz (Zeitschrift)
Englisch
Flame Propagation Through Combustible Particle Clouds
| British Library Conference Proceedings | 2001
Computational investigation of flame characteristics of a non-propagating shrub fire
| British Library Online Contents | 2016