scholarly journals A theory of the dependence of the rate of detonation of solid explosives on the diameter of the charge

1947 ◽  
Vol 189 (1018) ◽  
pp. 415-426 ◽  
Keyword(s):  
Detonation Wave ◽  
Chemical Reaction ◽  
Cylindrical Charge ◽  
Solid Explosive ◽  
Metal Case ◽  
Rate Of Reaction ◽  
Velocity Of Detonation ◽  
Solid Explosives ◽  
Different Diameters

The velocity of a detonation wave, in a cylindrical charge of solid explosive, is shown to be dependent on the diameter of the charge, and the relation between the velocity and the diameter is calculated. It is shown that this effect depends upon the rate of the chemical reaction occurring in the front portions of the detonation wave, and that it is possible, therefore, to determine this rate of reaction by measuring the velocity of detonation in bare charges of different diameters. The effect of a metal case surrounding the charge is also briefly discussed.

Numerical Simulation on Detonation Process in Variable-Section Charge under Condition of End-Point Detonation Model

2015 ◽  
Vol 799-800 ◽  
pp. 728-733
Author(s):  
Jun Ting Yin ◽  
Gang Li
Keyword(s):  
Numerical Simulation ◽  
Detonation Wave ◽  
Structure Design ◽  
Practical Significance ◽  
Cylindrical Charge ◽  
Oblique Collision ◽  
End Point ◽  
Variable Section ◽  
Velocity Of Detonation ◽  
Detonation Process

when detonation wave is spreading in cylindrical charge which has a shell constraint, the border of the shell will reflect the detonation wave, reflection wave still has a strong influence on charge’s centerline. Compared with cylindrical charge, the influence of variable-section charge’s stack reflection wave on centerline is unsteady, relating to the gradual trends height of section area. On the condition of end-point detonation, doing the numerical simulation on detonation process of equal-section charge 、reduced-increased charge and increased-reduced charge, analyzing the pressure and velocity of detonation products on position of centerline, founding in the range of gradually decreasing section al, detonation wave through reflecting and then occur oblique collision that induce the pressure increasing rapidly. Doing the numerical simulation on variable-section charge’s detonation, promoting the understand of the reflection wave mechanism and the velocity of detonation product, this can be a practical significance to further improve the charge structure design and realize the efficient utilization of detonation energy.

scholarly journals The Influence of Pipe Bending Curvature on H2-O2 Gaseous Detonation Wave Front

2021 ◽  
Vol 11 (9) ◽  
pp. 3951
Author(s):  
Hui Zhao ◽  
Huiyuan Li ◽  
Haitao Zhao ◽  
Leisheng Li ◽  
Jian Li
Keyword(s):  
Detonation Wave ◽  
Pressure Distribution ◽  
Wave Front ◽  
Cell Size ◽  
Chemical Reaction ◽  
Cellular Structure ◽  
Gaseous Detonation ◽  
External Boundary ◽  
Propagation Characteristics ◽  
Detonation Wave Front

The influence of different bend curvatures on the detonation wave propagation was analyzed by an advanced numerical simulation system. The mechanism of propagation properties is revealed by cellular structure, internal and external boundary pressure distribution, propagation process of detonation wave and chemical reaction. The cellular structure and detonation wave front of bend with different curvature are very different. The simulation results show that the detonation wave with regular cell structure propagating through the curved parts induces detonation cell size increased by diffraction near the inner wall while detonation reflected on the bottom surface resulting in decrease of cell size. Detonation wave was affected by the rarefaction wave and compression wave in the bent pipe. The pressure distribution of the bend shows that the peak pressure in the 450 curvature is the largest, which should be paid more attention in industrial design. The chemical reaction could indicate the propagation characteristics of detonation wave, and different propagation characteristics have different profiles of chemical components.

The formation and development of oblique detonation wave with different chemical reaction models

2021 ◽  
pp. 106964
Author(s):  
Hongbo Guo ◽  
Xiongbin Jia ◽  
Ningbo Zhao ◽  
Shuying Li ◽  
Hongtao Zheng ◽  
...  
Keyword(s):  
Detonation Wave ◽  
Chemical Reaction ◽  
Oblique Detonation Wave ◽  
Reaction Models

scholarly journals An electrical method of determining the velocity of detonation of explosives

1924 ◽  
Vol 105 (731) ◽  
pp. 282-298 ◽  
Keyword(s):  
Detonation Wave ◽  
Detonation Velocity ◽  
Detonation Pressure ◽  
Electrical Method ◽  
Vapour Density ◽  
Velocity Of Detonation ◽  
Set Up

When a layer of molecules in a mass of explosive detonates, the change is transmitted throughout the mass, and the velocity with which the transmission takes place is called the rate of detonation. It has been shown that the pressure p set up in the front of a detonation wave can be written p = velocity of detonation × velocity of vapour × density, so that explosives with high rates of detonation will have correspondingly high detonation pressures and consequently high destructive properties. A glance at the accompanying table [ see Robertson: 'J. C. S.,' vol. 119, p. 1 (1923)], which includes also values for the heat produced during detonation, will show that this is the case:- The pressure developed by tetryl is more than six times that developed by gunpowder, but the number of calories liberated at detonation by 1 gm. is only 1·8 times as great. The detonation pressure therefore depends not only on the amount of energy liberated, but also on the rate at which it is liberated. Rate of detonation becomes therefore at once one of the most important constants in explosive technology.

scholarly journals Effect of Initiation Location within Blasthole on Blast Vibration Field and Its Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Qidong Gao ◽  
Wenbo Lu ◽  
Zhendong Leng ◽  
Zhaowei Yang ◽  
Yuzhu Zhang ◽  
...  
Keyword(s):  
Detonation Wave ◽  
Forward Direction ◽  
Phase Delay ◽  
Cylindrical Charge ◽  
Blast Vibration ◽  
Vibration Field ◽  
Delay Effects ◽  
Acting Mechanism ◽  
Experimental Approaches ◽  
Drill And Blast

In drill and blast, the explosive filled in each blasthole is cylindrically shaped and generally initiated by the detonator. Thus, the effect of the initiation location must be addressed, as it determines the detonation direction along the entire column explosive. In this paper, the effect of the initiation location on blast vibration field and its acting mechanism were comprehensively investigated through the theoretical, computational, and experimental approaches. The results indicate that the initiation location plays an important role in the blast vibration filed of the cylindrical charge. The underlying effect of the initiation location can be regarded as the combined results of the energy distribution and phase delay effects of the column explosive source. The behavior of the rock mass in the single-hole blasting experiment demonstrates that the explosion energy is preferentially transmitted to the forward direction of the detonation wave. The seed wave-based computation model verifies that owing to the phase delay effect, the blast vibration field of the cylindrical charge is not uniformly distributed and is strengthened at the forward direction of the detonation wave. The production blasting experiment indicates that the ground PPV under bottom initiation is 61.3%∼211.7% larger than that under top initiation. In addition, the effect of the initiation location is sensitive to the charge length L and the denotation velocity D. Meanwhile, the effect of the initiation location vanishes with distance. The present study provides valuable reference for understanding the effect of the initiation location on blast vibration in drill and blast.

scholarly journals A Zel’dovich–von Neumann–Döring-like detonation wave in a multi-temperature mixture

2019 ◽  
Vol 869 ◽  
pp. 674-705 ◽  
Author(s):  
Damir Madjarević ◽  
Srboljub Simić ◽  
Ana Jacinta Soares
Keyword(s):  
Detonation Wave ◽  
Chemical Reaction ◽  
Wave Structure ◽  
Jump Discontinuity ◽  
Theory Approach ◽  
Reaction Heat ◽  
Von Neumann ◽  
Detonation Structure ◽  
Reversible Chemical Reaction ◽  
Non Equilibrium

The detonation wave structure is analysed in a binary mixture undergoing a reversible chemical reaction represented by $A_{r}\rightleftharpoons A_{p}$. It is assumed that the flow satisfies the proper basic assumptions of the Zel’dovich–von Neumann–Döring (ZND) detonation model, namely the flow is one-dimensional and the shock is represented by a jump discontinuity, but the assumption of local thermodynamic equilibrium is disregarded. This allows us to deeply investigate the coupling between the detonation structure of overdriven detonations and its chemical kinetics. The thermodynamic non-equilibrium effects are taken into account in the mathematical description, using the model of a multi-temperature mixture developed within extended thermodynamics, which has been proved to be consistent with a kinetic theory approach. The reaction rate is then enriched with terms that take into account the temperatures of the constituents. The results show that the temperature difference between components within the detonation wave structure, which describes thermodynamic non-equilibrium, is driven by the chemical reaction. Numerical computations confirm the existence of non-monotonic profiles in the reaction zone of overdriven detonations which are sensitive to changes in the activation energy and reaction heat.

Sympathetic detonation and initiation by impact

1958 ◽  
Vol 246 (1245) ◽  
pp. 274-281 ◽  
Keyword(s):  
Kinetic Energy ◽  
Detonation Wave ◽  
High Speed ◽  
Incident Shock ◽  
Shock Pressure ◽  
The Body ◽  
Detonation Pressure ◽  
Air Gaps ◽  
Solid Explosives ◽  
Very High

High-speed photographic techniques have been used to investigate the sympathetic detonation of solid explosives by shocks propagated across air gaps and solid barriers. It has been observed that initiation takes place within the body of the receptor stick, rather than at the surface, if the shock pressure is appreciably less than the detonation pressure. The depth in the receptor at which initiation occurs depends systematically upon the pressure of the incident shock ; the lower the pressure the deeper the point of initiation. Detonation always occurs at the shock front, but, under the conditions of the experiments completed thus far, does not propagate backward into the preshocked explosive. The propagation velocity of the detonation wave in the receptor is, at least initially, greater than that observed under ordinary conditions. Studies of initiation by impact have shown many points of similarity. Initiation takes place within the body of the target explosive block, at a point ahead of the striking projectile, except at very high velocities of impact. The depth in the explosive and the distance ahead of the projectile at which initiation occurs depend mainly upon the velocity of the projectile and upon the shape of its front. In agreement with previous work, it has been shown that the kinetic energy of the impacting projectile is not a basic parameter in determining the probability of initiation or the conditions under which it occurs.

Observations of detonation in solid explosives by microwave interferometry

1958 ◽  
Vol 248 (1255) ◽  
pp. 499-521 ◽  
Keyword(s):  
Activation Energy ◽  
Detonation Velocity ◽  
Fringe Pattern ◽  
Detonation Front ◽  
Beam Theory ◽  
Kcal Mole ◽  
Zone Length ◽  
Solid Explosive ◽  
Interferometric Technique ◽  
Solid Explosives

Detonation processes have been observed in narrow, heavily confined, columns of solid explosive by a new microwave interferometric technique. The technique is described and a multiple-beam theory of fringe shape is given. The location, with respect to the detonation front, of the surface reflecting the microwaves is discussed. Detonation velocity as a function of distance along the column is derived from an oscilloscope display of the fringe pattern. The calculation of the detonation velocity requires a knowledge of the wavelength of the microwaves in the explosive. For this purpose the relative permittivities of a number of explosives are given as a function of their pressed density. The accuracy and applications of the method are discussed. Experiments on tetryl are described in which the technique is evaluated by observing the detonation velocity for a range of densities, and is applied to resolution of the velocity transient during growth to detonation. A simple theory of growth is used to estimate the reaction zone length (0.4 mm) and the activation energy (2 kcal/mole) in the detonation of tetryl.

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