detonation & deflagration difference(basic)
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DETONATIONAND
DEFLAGARATION
- Jigar D
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Deflagration (Lat: de + flagrare, "to burn down")
Subsonic combustion propagating through heat transfer; hot burning materialheats the next layer of cold material and ignites it.
A deflagration is characterized by a subsonic flame propagation velocity,typically far below 100 m/s, and relatively modest overpressures, say below
0.5 bar.
Most "fire" found in daily life, from flames to explosions, is deflagration.
Eg. Combustion in Gas stove, Fuel air mixture in IC Engine, Rapid burning ofgunpowder in firearm, pyrotechnic mixture in fireworks.
Applications in mining, demolition and stone quarrying via gas pressureblasting.
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Detonation (detonare, meaning “to expend thunder”)
Combustion propagation is of a powerful pressure wave that compresses theunburnt gas ahead of the wave to a temperature above the autoignition
temperature.
The velocity of detonation in solid and liquid explosives is much higher than
that in gaseous ones.
A detonation is characterized by supersonic flame propagation velocities,
perhaps up to 2000 m/s, and substantial overpressures, up to 20 bars. Detonation is most often used for explosives and the acceleration of
projectiles.
Pulse detonation engines use the detonation wave for aerospace propulsion.
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The Hugoniot-diagram
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Deflagration to Detonation
The natural acceleration of a flame in a long pipe
The forced acceleration of a less confined mixture
within a region containing obstacles
In both cases, gas phase turbulence enhances combustion rates to a point where a shoahead of the flame front. If further flame acceleration occurs, the leading shock waveuntil a transition to detonation occurs.
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Deflagration-to-Detonation Transition
(DDT)
Deflagration-to-detonation transition (DDT) is the transient phenomenonresulting from the acceleration of a deflagration flame to detonation via
combustion-generated turbulent flow and compressive heat effects.
During the DDT, the initial peak pressure reached is higher than the final
pressure reached when the stable detonation phase occurs, and thedetonation wave is described as “overdriven.”
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Deflagration to Detonation Transition Ca
Industrial Accidents1970 Propane vapor cloud explosion in Port Hudson
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Deflagration to Detonation Transition Ca
Industrial AccidentsThe Flixborough disaster
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Deflagration to Detonation Transition Ca
Industrial AccidentsThe1989 Phillips Disaster in Pasadena, Texas
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Deflagration to Detonation Transition Ca
Industrial AccidentsThe damage observed in the Buncefield fire, see the 2005 Hertfordshire Oil Storage Ter
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