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The Chapman–Jouguet condition holds approximately in detonation waves in high explosives.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.
However, before this wave arrives, heat conduction via the deflagration wave would have arrived and already initiated the chemical reaction. Thus, heat conduction is not negligible for this case and therefore spontaneous wave is not possible. Consider now the case < <. The spontaneous wave propagates sufficiently faster so that heat conduction ...
The simplest theory to predict the behaviour of detonations in gases is known as the Chapman–Jouguet (CJ) condition, developed around the turn of the 20th century. This theory, described by a relatively simple set of algebraic equations, models the detonation as a propagating shock wave accompanied by exothermic heat release.
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.
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 ...
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]
The velocity of detonation is an important indicator for overall energy and power of detonation, and in particular for the brisance or shattering effect of an explosive which is due to the detonation pressure. The pressure can be calculated using Chapman-Jouguet theory from the velocity and density.
The US Navy has been pushing development. [11] Researchers at the Naval Research Laboratory (NRL) have a particular interest in the capability of detonation engines such as the RDE to reduce the fuel consumption of their ships. [12] [11] Several obstacles must still be overcome in order to use the RDE in the field. As of 2012, NRL researchers ...