Unstable detonations

Produced by action of acetylene on sodium gold thiosulfate (or other gold salts), the acetylide is explosive and readily initiated by light impact, friction or rapid heating to 83°C [1], This unstable detonator is noted for high brisance [2],... 

Definition of deton, expln de-flgrn) 44-8 (Ideal deton) 48-50 (Nonideal deton) 50-7 (Transient and unstable deton waves) 57-60 (The jumping deton) 61-90 (Thermohydrodynamic theory of deton) 61-6 (Equation of state in deton of condensed expls) 66-8 (The Chapman-Jouguet postulate) 68-75 (The deton reaction zone in gases) 75-7 (Reaction zone in nonideal deton in gases) 77-9 (Reaction zone in condensed expls) 79-87... 

Detonation Transients and Unstable Detonation Processes. Allen et al (Ref 1) made detonation velocity vs chge length. measurements on RDX (—65+100 mesh), fine grained TNT (—35 —150) coarse, low-density TNT (—8+10) 50/50 fine-coarse TNT, cast TNT, low-density. mixts of 80/20 TNT/AN, and mixts of 90/10 AN/RDX. Deton velocities were measured by a rotating mirror streak camera and by the pin oscillograph technique, in most cases simultaneously Their exptl data showed six different types of velocity transients ... 

Detonation (and Explosion), Unstable, See Detonation (and Explosion), Steady and Nonsteady State in and also Detonation (and Explosion), Transients and Unstable Detonation Processes... 

Detonation Wave, Metastable. See Ref 52, p 51 and under Detonation Wave, Transients in Propagation Transient, Anomalous, and Metastable (Unstable) Detonation Waves... 

Ref A.K. Oppenheim, 4thSympCombstn (1952XPub 1953), PP 471-80 Ibid, JAppl Mechanics 20 115(1953) and Ref 66,pp 171-73 [See also Detonation Waves Transients in Propagation of Transient, Anomalous and Metastable (Unstable) Detonation Waves and "Detonation Wave Transient, Three - Dimensional ]... 

Reactions with "normal" kinetics were chosen for these examples because they are easiest to understand. Similar effects may arise under isothermal conditions if the reaction itself involves two different, contending pathways or steps whose dependences on a reaction parameter correspond to intersecting curves. The interplay of chain branching and termination in a chain reaction is a case in point—even though the reaction can hardly be kept isothermal once it has become unstable. Detonation would result even under hypothetical isothermal conditions ... 

These two forms of explosion of liquid explosives can interchange with each other. In certain case, combustion may transform into unstable detonation and further evolute into stable detonation. 

For the study of the unstable detonation, Galyparin and Svedov have used the probe illustrated in Figure 4.19. The operating principle of this probe is based on the change of the probe resistance, as previously described. However, the specific feature of the probe is its pulse supply from a constant current source. 

Such continuous determination of detonation velocity enables the shufy of unstable detonation processes, including the deflagration-to-detonation transition. Some examples of the application of this method are illustrated in Figures 4.25-4.27. 

The details of the reaction zone structure are very dependent on the properties of the equation of state for the mixture of undecomposed explosive and detonation products. The amount of overdrive necessary to obtain a steady detonation and the period and magnitude of the oscillation of an unstable detonation are not as dependent upon the equation of state details, but they are very dependent on the activation energy. 

SIN calculations for the Erpenbeck and Fickett ideal gas detonation model, as shown in Table 1.3 and Figure 1.18 resulted in both stable and unstable detonations. The results agree with Erpenbeck s non-viscous linearized analysis and Fickett and Wood s sharp-shock solutions. For example, for the unstable case of E = 50,7 = 1-2, Q = 50, and / = D /Dqj = 1.6, with enough viscosity to smear the shock front over 10 cells, the same period and final amplitude was obtained as Fickett and Wood with no viscosity. Additional comparisons will be made in the next section. 

Fig. 5.20 Chart of the blast processes in the semi-confined near ceiling HAM layers [27] 1 - slow deflagration 2 - fast deflagration 3 - unstable detonation 4 - detonation...

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