Detonations development

In an enclosure, a peak for initial pressure ratio for a deflagration generally can exceed 8 1 of the initial pressure. The pressures may build to a ratio of 40 1 (reflected pressure) times the initial pressure when a detonation develops. This is the reason detonations can be so disastrous. Their final pressure, when built on a deflagration peak pressure as a base or initial pressure, can be extremely high. 

Detonations will also propagate through liquid fuel droplet dispersions (sprays) in air and through solid-gas mixtures such as dust dispersions. Volatility of the liquid fuel plays an important role in characterizing the detonation developed. For low-volatility fuels, fracture and vaporization of the... 

The hot gases from the percussion primer permeate thru the baffle and initiate the BkPdr delay pellet, which burns under the reproducible pressure conditions which are obtained within the delay element housing, with a delay time of 0.035 sec. When the BkPdr element has burned thru, a spit of flame impinges on a detonator loaded with LA a true detonation develops and progresses successively thru the Tetryl-loaded lead-out, the Tetryl-loaded booster lead-in, the Tetryl-loaded booster and Explosive D (Ammonium Picrate) -loaded main (or bursting) charge of the projectile. 

Only one instantaneous US Army electric detonator is described in Ref 23- It is M36, which is, accdg to Tweed (Ref 42b, p 653), the first electric detonator developed by the Army Ordnance Corps when it was required during WWII to equip airplanes with electri-... 

In the ammonals not contg carbon, the mixture of TNT and AN detonate, developing a very high temp, which causes volatilization or the AI powder. Secondary reactions which follow, involve the oxidation of vaporized AI, either by air (if it is present) or by the products formed on deton of TNT and AN, such as COa and Ha0 ... 

Detonation developed in constricted tubes, super-compressed 4 D578... 

According to Medard [64] the rates of detonation developed with non confined nitrometriol cartridges, 30 mm dia., were ... 

Aniaufstrecke = detonation development distance 90 Antenne - bus wire 47 antigrisouteux - permitted explosives 248... 

The detonation development distance, especially that of less sensitive explosives, is strongly affected by the consistency, density and the cross-section of the charge. 

Primary explosives, when set off by a flame, must detonate immediately, and their detonation development distance must be as short as possible. 

Silver fulminate is much more sensitive than mercury fulminate. Since its detonation development distance is very short, its initiation effect is superior to that of mercury fulminate, but the compound is too sensitive to be used commercially. 

Indirect initiation involves a transition from deflagration to detonation. This process has been studied extensively for waves propagating in tubes, and many reviews are available [14]-[28]. The detonation develops... 

Figure 17 shows the effect of pressure on the density and effectiveness of lead azide in the above detonators. Streak-camera and contact-pin measurements of sectioned detonators showed that high-order detonation develops in the center of the 0.060-in. (0.152-cm) -thick layer oflead azide. 

Assuming the checks for explosibility have not revealed a hazard from deflagration or detonation, development work can proceed. Information is then required on the exothermicity of the proposed reaction ... 

A typical sequence of pressure profiles for the initiation of nitromethane is shown in Figure 3.6. The shock travels into the explosive shock heating occurs and results in chemical decomposition. Explosion occurs at the rear boundary, and a detonation develops with the C-J pressure and velocity characteristic of the explosive at the shocked pressure and density. Because these pressures and velocities are often much larger than the explosive normal maximum C-J performance, these detonations in the shocked explosive are called super detonations. The detonation wave overtakes the shock wave and then decays to the normal density C-J pressure and velocity. An animation of the shock initiation of nitromethane is on the CD-ROM in the /MOVIE/NM.MVE directory and in the PowerPoint HOMO.PPT in the /CLASS.PPT/CHAPT3 directory. 

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