Permitted explosive detonation pressure

The term Q is zero for the nonreaction R-H curve. These eqs are important in explosives theory. They permit correlation of the explosive characteristics of substances with other physical and chemical properties, and allow determination of the temperature and pressure conditions within the detonation zone... 

If, however, the expl is under confinement, the deflagration might undergo transition into explosion or detonation. Confinement permits rapid increase in pressure with consequent rapid increase in the rate of deflagration. If the rate reaches the value of 1000-1800 in/sec, it rs already not deflagration but "low-order detonation. If the rate increases to 5000 m/sec, the detonation is "high-order ... 

Figure 2.18 Calculated and experimental water shock and explosive-water interface profiles for a 5-cm-radius cylinder of ANFO confined by water. At the C-J plane, 55% of the ammonium is unreacted. The ammonium nitrate is permitted to react with the detonation products at a linear rate with decreasing pressure. The experimental profile is shown by circles. The isobar interval is 1 kbar.

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