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Deflagration (Lat: de + flagrare, 'to burn down') is subsonic combustion in which a pre-mixed flame propagates through an explosive or a mixture of fuel and oxidizer. [ 1 ] [ 2 ] Deflagrations in high and low explosives or fuel–oxidizer mixtures may transition to a detonation depending upon confinement and other factors.
The phenomenon is exploited in pulse detonation engines, because a detonation produces a more efficient combustion of the reactants than a deflagration does, i.e. giving a higher yields. Such engines typically employ a Shchelkin spiral in the combustion chamber to facilitate the deflagration to detonation transition. [2] [3]
Compared with deflagration, detonation doesn't need to have an external oxidizer. Oxidizers and fuel mix when deflagration occurs. Detonation is more destructive than deflagrations. In detonation, the flame front travels through the air-fuel faster than sound; while in deflagration, the flame front travels through the air-fuel slower than sound.
However, they are used as solid propellants; in normal use, they undergo deflagration rather than detonation. Smokeless powder made autoloading firearms with many moving parts feasible (which would otherwise jam or seize under heavy black powder fouling).
It states that the detonation propagates at a velocity at which the reacting gases just reach sonic velocity (in the frame of the leading shock wave) as the reaction ceases. [ 1 ] [ 2 ] David Chapman [ 3 ] and Émile Jouguet [ 4 ] originally (c. 1900) stated the condition for an infinitesimally thin detonation.
Witnesses have revealed what they saw take place at the moment of impact during the horrifying collision between an American Airlines jet and an Army helicopter over the Potomac River. On ...
A schematic diagram of a shock wave situation with the density , velocity , and temperature indicated for each region.. The Rankine–Hugoniot conditions, also referred to as Rankine–Hugoniot jump conditions or Rankine–Hugoniot relations, describe the relationship between the states on both sides of a shock wave or a combustion wave (deflagration or detonation) in a one-dimensional flow in ...
A fast-spreading wildfire that erupted this week northwest of Los Angeles roared from nothing to nearly 10,000 acres − in a matter of hours.