Detonation wave parameters

V.M. Bozomolov LM. Voskoboinikov, Calculation of Detonation Wave Parameters for Mixtures of Explosives with Inert Additives , FizGoreniyaVzryva 6(2) 183—6 (1970) 47)... 

Dremin Pokhil (Ref 58) detd deton wave parameters in TNT, RDX, NG and NMe. Zubarev Telegin (Ref 76) detd parameters in some condensed expls and Hazal Comburini (Ref 78) calculated characteristics of explosion waves in pure and diluted Hydrazoic Acid... 

Dremin P.F.. Pokhil, DokAkadN (PhysChem Section) 128, 839-41 and 989-91 (1959) (Detonation wave parameters of TNT, RDX,... 

The experimental methods for the determination of the detonation wave parameters can be classified into two groups. The first, the so-called internal methods group, includes the methods by which detonation parameters are directly determined. These are the determination of the mass velocity of the detonation products by the electromagnetic particle velocity gauge method, direct determination of the detonation pressure by a manganin pressure gauge, determination of the mass velocity of the detonation products by the flash X-ray technique, etc. The time resolution of these methods can be on a nanoseconds scale, which is still not sufficient for fully reliable study of a very narrow chemical reactions zone, and in particular, of a shock wave front. 

In order to obtain the plot of shock wave versus plate thickness, it is necessary first to determine the plate free-surfece velocity as a function of plate thickness. Then, the corresponding pressure value should be calculated as a function of plate thickness on the basis of the relationship between detonation wave parameters (Eqs. (4.1)-(4.4)). 

The determination of the detonation wave parameters and its structure on the basis of the determination of the shock wave velocity in an inert and optically transparent material using a laser follows the same principles as in the case of the aquarium test. However, if compared to the standard aquarium test, it is characterised by a better time resolution, on a nanosecond scale. Thus, this technique allows the study of the detonation wave structure, i.e., the chemical reaction zone width and the duration time (Ashaev et al., 1988). 

Determination of the Detonation Wave Parameters Using Flash X-Ray PhotograpJ ... 

The flash X-ray radiographic technique used for the determination of the detonation wave parameters is based on time-dependent tracing of the position of thin metal foils moving together with detonation products behind the detonation wave front at the same velocity. Therefore, viewing the movement of the foils, one obtains the velocity of detonation products behind the detonation wave front, i.e., their mass velocity (Chick et al., 1985 Dorokhin et al., 1988 Huiling et al, 1985 Trimble et al, 1981). On the basis of that velocity, other detonation parameters can be calculated. 

For the determination of the shock wave parameters in different media, the methods identical to those used for the determination of detonation wave parameters can be applied to a large extent. 

Propagation of a detonation wave depends on a number of physical parameters ... 

FIGURE 5.13 Variation of physical parameters through a typical detonation wave (see Table 5.5). 

The extent to which a detonation will propagate from one experimental configuration into another determines the dynamic parameter called critical tube diameter. It has been found that if a planar detonation wave propagating in a circular tube emerges suddenly into an unconfined volume containing the same mixture, the planar wave will transform into a spherical wave if the tube diameter d exceeds a certain critical value dc (i.e., d > dc). II d < d.. the expansion waves will decouple the reaction zone from the shock, and a spherical deflagration wave results [6],... 

Dremin et al (Ref 12) gives values for the following parameters of RDX TNT D=detonation velocity, Uj = velocity of detonation products at the detonation-wave front, and P = Chapman-Jouguet-plane pressure at various densities... 

Characteristics of Detonation Waves. Same as Parameters of Detonation Waves... 

Ideal deton velocities correspond to a composition of the products of deton which depend only on the contents C - H - N - O and the temp pressure of deton all the parameters of the ideal deton wave of a mixed HE can be calcd exactly the same way as is done for individual HE s. It should only account for the peculiarity of the progress of the reaction in a deton wave of mixed HE s, associated with.the fact that at the start the expl components are decompd in a specific volume and then a prereaction takes place in the deton products. In the case when the decomposition of the deton products in the first stage is energetically more favorable than after the subreaction, the first stage of the reaction is responsible for the ideal velocity. This applies to mixtures of the type such as Pentolite... 

The calculation of parameters of overcompressed wave formed on detonation of 2H2+O2 mixture, has shown that upon transition from the wide pipe to the narrow one, an overcompressed wave should arrise in the narrow pipe for which the pressure is 1.36 times greater than the pressure in the normal detonation wave. In this case the velocity of overcompressed wave was equal to 1.04 times the vel of normal deton wave, but... 

G.B. Kistiakowsky, "Theory of Stationary Detonation Waves , pp 952- 55 and "Calculation of Detonation Parameters, pp 955-59 in Kirk Othmer 5 (1950) (Not found in 2nd edition of Kirk Othmer)... 

G.S- Telegin, DoklAkad N 147, 1122-25 (1962) CA 58, 7779 (1963) (Calculation of Parameters of Detonation Waves of Condensed Explosives) 77) H. Freiwald R. Schall, Explosivst 10, 1-5 (1962) (Detonation Waves) 77a) N.E. Hoskin B.W. Pearson, "Finite Difference Methods for One- Dimensional Unsteady Flow ... 

Jouguet, (Jacques-Charles) Emile (1871 — 1943). French physicist, general inspector of mines and professor of mechanics ficole des Mine, ficole Poly technique, member French Academy of Science (1930). He was the author of Me-canique des Explosifs (1917) and conducted research on wave diffusion, movement of fluids, explosives and fundamental work on the hydro-dynamic theory of detonation. His name is associated with that of Chapman-in the famous Chapman-Jouguet condition. In their honor parameters of a steady detonation wave are usually designated by the subscript CJ... 

Gas detonation at reduced initial pressures were studied by Vasil ev et al (Ref 8). They point out the errors in glibly comparing ideal lossless onedimensional computations with measurements made in 3-dimensicnal systems. We quote In an ideal lossless detonation wave, the Chapman-Jouguet plane is identified with the plane of complete chemical and thermodynamic equilibrium. As a rule, in a real detonation wave the Chapman-Jouguet state is assumed to be the gas state behind the front, where the measurable parameters are constant, within the experimental errors. It is assumed that, in the one-dimensional model of the detonation wave in the absence of loss, the conditions in the transient rarefaction wave accompanying the Chapman-Jouguet plane vary very slowly if the... 

Let us turn to detonation theory. By the turn of the century the rule for calculating the velocity of a detonation wave and other parameters using only thermodynamic data and the conservation laws was known. It appeared that the chemical kinetics of the transformation of the original explosive substance or mixture into the final reaction products did not play any role, and that it was enough to consider only the initial and final states. 

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