Detonation condensed phase

Condensed Phase Detonations Condensed phase materials are high explosives and propellants. Such materials have detonated during manufacturing, transportation, storage, and use. Certain compounds of this type decompose almost instantly in a violent reaction. Most produce hot gases. 

Duff, R.E., Invited Review Summary of Papers on Condensed Phase Detonation, in Fourth Symposium (International) on Detonation, ACR-126 (edited by Jacobs, S.J.), Office of Naval Research, Washington, DC, 1966, pp. 198-201. 

The diazirines are of special interest because of their isomerism with the aliphatic diazo compounds. The diazirines show considerable differences in their properties from the aliphatic diazo compounds, except in their explosive nature. The compounds 3-methyl-3-ethyl-diazirine and 3,3-diethyldiazirine prepared by Paulsen detonated on shock and on heating. Small quantities of 3,3-pentamethylenediazirine (68) can be distilled at normal pressures (bp 109°C). On overheating, explosion followed. 3-n-Propyldiazirine exploded on attempts to distil it a little above room temperature. 3-Methyldiazirine is stable as a gas, but on attempting to condense ca. 100 mg for vapor pressure measurements, it detonated with complete destruction of the apparatus." Diazirine (67) decomposed at once when a sample which had been condensed in dry ice was taken out of the cold trap. Work with the lower molecular weight diazirines in condensed phases should therefore be avoided. 

Chemical equilibrium methods provide useful predictions of the EOS of detonation processes and the product molecules formed, but no details of the atomistic mechanisms in the detonation are revealed. We now discuss condensed-phase detonation simulations using atomistic modeling techniques to evaluate reaction mechanisms on the microscopic level. 

Gas-phase results provide insight into the reaction pathways for isolated HE molecules however, the absence of the condensed-phase environment is believed to affect reaction pathways strongly. Some key questions related to condensed-phase decomposition are as follows (1) How do the temperature and pressure affect the reaction pathways (2) Are there temperature or pressure-induced phase-transitions that play a role in the reaction pathways that may occur (3) What happens to the reaction profiles in a shock-induced detonation These questions can be answered with condensed-phase simulations, but such simulations would require large-scale reactive chemical systems consisting of thousands of atoms. Here we present results of condensed-phase atomistic simulations, which are pushing the envelope toward reaching the required simulation goal. 

Shock waves in the near and far fields usually result from condensed phase detonations, or from an extremely energetic vapor cloud explosion. Most vapor cloud deflagrations will give rise to pressure waves in the near field which may propagate as a shock wave, or shock-up, in the far field. 

In the most severe case of a condensed phase material detonation, a substantial portion of a process unit may be completely destroyed with only a crater remaining in the location of the equipment. Where does an investigator start when faced with almost nothing but a crater This situation presents significant challenges. The investigation team is faced with... 

Measurement of the Detonation-Front Structure in Condensed-Phase Explosives , Ibid, 863-67 11) W.E. Gordon, "Detonation Limits in Condensed Explosives , 4thONRSympDeton(1965), 179-97 12) M.C. Chick, "The Effect of... 

The sudden increase in temperature and pressure "shocks the material into condition to undergo chemical reaction. Even in a condensed-phase material, temperature rises of several hundred degrees at certain critical points ("hot spots ) can be brought about in this way. Furthermore, the material ahead of "detonation front is at rest and... 

Detonation and explosion in condensed phase (solid or liquid as opposed to gas, dust or vapor) explosives were briefly discussed in Vol 3 of our Encycl, p C495-R, under "Condensed Explosives , but the following comments of C.G. Dunkle (Ref 22) may be added. His discussion is based mainly on the information obtained at the lOthSympCombstn (1964) and other Symposiums... 

Detonation in gases has been mote thoroughly investigated than in condensed phases, and continues to receive the major share of attention. In a broad sense the chain of events is the same in both cases (Ref 7, p 2), but in gases is spread out in both space and time, being therefore more easily observed... 

Refs 1) J. Taylor, PrRoySoc 204A, 30-1 (1950) (High- and low-regimes in condensed expls) 2)-Taylor (195 2), 87-110 (Deton in condensed expls yielding only gaseous products) 111-38 (Deton in expls whose products contain a condensed phase) 3) E. Sanger CR 235, 461-63(1952) (Deton of liquid and solid expls) 4) E. Haeuseler, Explo-sivst 1953, 64-8 (Deton of liquid expls)... 

A.W. Campbell et al, PhysFluids 4, 498-510(1961) (Shock initiation of deton in liquid expls) 15a) Ibid, pp 511-22(1961) (Shock initiation in solid expls) 16) R.O. Miller, "Estimating Caloric State Behavior in Condensed-Phase Detonations , pp 65-74 in S.S. Penner F.A. Williams, "Detonation and Two-Phase Flow , Academic Press, NY (1962) 16a) R.F. Chaiken, A Kinetic... 

Duff, "Summary of Papers on Condensed Phase Detonation" (Invited Review), Ibid, pp 198-201 20) PATR 2700, Vol 3(1966),... 

For condensed explosives whose products of detonation contain a condensed phase, Taylor (Ref 7, p 114) gives ... 

Pure shock waves) 4) G.B. Kistiakowsky, p 951 in Kirk Othmer 5 (1950), pp given in the text (Not included in the 2nd edition) 5) Corner, Ballistics (1950), 100-01 (Corner Noble-Abel equations of state) 6) SAC MS, Ballistics (1951), 18 (Covolume and equation of state of propint gases) 7) Taylor(1952), 34 (Boltzmann and Hirschfelder Roseveare equation of state for the expln products) 69-72 (Rankine-Hugoniot equation of state) 87-98 (Abel, Boltzmann and other equations of state applicable to deton of condensed expls yielding only gaseous products) 114 (Equations of state applicable to deton of condensed expls whose products contain a condensed phase)... 

B.G. Craig, "Measurements of the Detonation-Front Structure in Condensed-Phase Explosions , lOthSympCombstn (1965), pp 863-67 6) W.C. Davis et al,... 

Note 1 Accdg to Dunkle (Ref 12) "The perceptiveness of the author (Apin) of this article (meaning Ref 6) over 20 years old is amazing. The idea that the detonation front is heterogeneous and of rough surface even in condensed-phase explosives is very much in favor now. Several papers and discussion at the 7thSympCombstn, August, 1966 in Berkeley, Calif bore on this point ... 

Definition of spike pressure and probability of its existence are briefly discussed in this Vol under Detonation (and Explosion) in Condensed-Phase Explosives". The so-called spike theory is discussed under "Detonation, Spike Theory in . A more detailed description is given by Cook (Ref 41, pp 69-87)... 

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