Wave front, detonation

The superior shaped-charge performance of Octol, as indicated previously, is limited by perturbances of the detonation wave front that af-... 

Jones assumed. It has, in fact, been shown experimentally by Herzberg et al (Ref 2, p 119) that the detonation wave fronts are curved and that the curvature increases as the charge diameter is reduced. A simple method by which this,curvature can be illustrated is provided by the use of a high-speed Streak Camera (same as "Smear Camera" described in Vol 2 of Encycl, p C16-L). 

M.A. Cook, "Detonation Wave Fronts in Ideal and Non-Ideal Detonation , Ibid, pp 382-400... 

The Langweiler model was attacked by Kistiakowsky Kydd (Ref 6) on the basis that the rarefaction wave cannot remain abrupt, as claimed by Langweiler, but must spread out in time. All classical theories of the deton wave front assume that rarefaction begins immediately behind the deton front... 

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... 

AnnPhys 10(IV), 645(1925) (Spherical detonations of CS2+3O2 mixture) 2) L.D. Landau K.P. Stanyukovich, DoklAkadN 46, 399(1945) (On the study of detonation in condensed explosives) 3) H. Jones Sc A.R. Miller, PrRoySoc 194A, 480-507(1948) (The detonation of solid explosives The equilibrium conditions in the detonation wave-front and the adiabatic expansion of the products of detonation) 3a) Cole, Underwater (1948), pp 81-83 4) J. 

Cook (1958), 99-106 (Detonation wave front) 20) Baum, Stanyukovich Shekhter (1959),598-624 (Teoriya tochecbnago vzryva) (Theory of point source explosion) 624-40 (Sfericheskii vzryv) (Spherical explosion)... 

The fundamental cause of the "pseudo-ideal deton vels that are observed in the progress by stages of the reaction at the deton wave front of mixed HE s is due to the kinetics of the decompn of the expl components. A whole series of factors have an influence on the rate of liberation of energy in the wave... 

Detonation Wave Front. See under Detonation Wave Shape and Density Properties and also in Refs 38, 44a, 51, 52 and 96 Following is an abstract of Ref 96 ... 

Detonation Wave, Spherical, Under this term are known detonation waves whose surface (front) is at all points equidistant from the center. The detonation wave front is in the form of a sphere and propagates outwardly in all directions... 

W.B.. Cybulsky et al, PrRoySoc 197A, 51-72 (1949) (Explosion waves and shock waves). 22a) H. Eyring et al, Chem Revs 4 69 (1949) (See in the text under "Radius of the Curvature of the Detonation Wave Front 23) G.I. Taylor,... 

Dynamics of combustion products behind plane and spherical detonation wave fronts in explosives )... 

CA 49, 10625 (1955) (Structure of detonation wave front of gases was studied by method of shock tube) (See its abstract under Detonation Wave Structure) 38a) R.E. Duff E. Houston, 2nd ONRSympDeton (1955), p 225 (See under Detonation Wave Structure Measurements in Condensed Explosives) 39) S. Minshall, JApplPhys 26, 463- 69 (1955) (Properties of elastic and plastic waves determined by pin contactors and crystals) 40) C.G. Dunkle, "Introduction to Theory of Detonation of Explosives, Syllabus of 21 Nov 1955 and Lecture Delivered at Picatinny Arsenal on 13 Dec, 1955 (Structure of the deton wave)... 

Mallory (Ref 19), Urtiew Kusubov (Ref 26b), Watson (Ref 26d), Persson (Ref 26c), Seely et al (Ref 26) Cook and co-workers (Ref 32) have shown similar effects in the detonation wave fronts of LE. However, inhomogeneities in the wave front were observed only for rather insensitive expls, particularly in expls diluted with inert additives. This is understandable if, as suggested by Shchelkin (Ref 8), the size of the inhomogeneities is determined by the reaction time of the expl under classical (C-J) conditions. For sensitive LE (eg, NG), these reaction times are short and inhomogenei-lties are too small to be resolved by instrumentation now available. The problem of wave front instability in all LE is still unresolved. There may be certain LE that behave classically, ie, their detonation fronts are stable, uniform and one dimensional (Ref 18)... 

On suitable initiation of a homogeneous liquid explosive, such as liquid nitroglycerine, the pressure, temperature, and density will all increase to form a detonation wave front. This will take place within a time interval of the order of magnitude of 10 12 s. Exothermic chemical reactions for the decomposition of liquid nitroglycerine will take place in the shockwave front. The shockwave will have an approximate thickness of 0.2 mm. Towards the end of the shockwave front the pressure will be about 220 kbar, the temperature will be above 3000 °C and the density of liquid nitroglycerine will be 30% higher than its original value. 

For a cylindrical pellet of an explosive composition the velocity of detonation will increase as the diameter of the explosive composition increases up to a limiting value. The detonation wave front for a cylindrical pellet at steady state conditions is not flat but convex as shown in Figure 3.6, where D is the axial detonation velocity and Dt is the detonation velocity close to the surface of the composition. 

Fig 7 The Time Dependent Histories of the Detonation Wave Front Shape and Pressure... 

Let us consider the propagation of a detonation wave in a tube, taking account of heat transfer and braking against the side walls of the tube. We will restrict ourselves to the one-dimensional theory in which heat transfer and drag are uniformly distributed over the entire cross-section of the tube. We denote by x the coordinate measured from the detonation wave front toward the unreacted gas, in the direction of wave propagation. It is in fact on this coordinate alone in the steady and one-dimensional theory that all the following quantities depend ... 

In the literature one encounters indications that in a slow chemical reaction not all the reaction heat is released in the detonation wave front, which in fact explains the lower velocity of detonation compared with that calculated according to the classical theory (Wendlandt [10], Lewis and Friauf [34], Rivin and Sokolik [35], Jost [12, 31]). 

In the theory developed the pressure and velocity in the discontinuity without chemical reaction (a shock wave, point C, Fig. 1 or 5) which forms a detonation wave front are higher than are conventionally assumed for detonation, i.e., at the moment when (to accuracy to within the losses) the chemical reaction has completed (point B, Fig. 1 or 5, conditions (6), (29) cf. Fig. 6). 

This also characterizes the very style of the experimental studies. Even until recently the hydrodynamic theory of the detonation velocity, which was excellently confirmed in experiments, created a sense of contentedness and did not inspire the search for the chemical reaction mechanism or investigation of the conditions at the detonation wave front. If our paper brings about new experimental studies which penetrate deeper into the essence of the phenomenon, then our task will have been accomplished. 

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