Detonation, explosion

Propellants and explosives are chemical compounds or mixtures that rapidly produce large volumes of hot gases when properly initiated. Propellants bum at relatively low rates measured in centimeters per second explosives detonate at rates of kilometers per second. Pyrotechnic materials evolve large amounts of heat but much less gas than propellants and explosives (see Pyrotechnics). 

A comparison of the characteristics associated with propellant burning, explosive detonation, and the performance of conventional fuels (see Coal Gas, NATURAL Petroleum) is shown ia Table 1. The most notable difference is the rate at which energy is evolved. The energy Hberated by explosives and propellants depends on the thermochemical properties of the reactants. As a rough rule of thumb, these materials yield about 1000 cm of gas and 4.2 kj (1000 cal) of heat per gram of material. 

Exothermic oxidation—reduction reactions provide the energy released in both propellant burning and explosive detonation. The reactions are either internal oxidation—reductions, as in the decomposition of nitroglycerin and pentaerythritol tetranitrate, or reactions between discrete oxidizers and fuels in heterogeneous mixtures. 

Computer codes are used for the calculational procedures which provide highly detailed data, eg, the Ruby code (70). Rapid, short-form methods yielding very good first approximations, such as the Kamlet equations, are also available (71—74). Both modeling approaches show good agreement with experimental data obtained ia measures of performance. A comparison of calculated and experimental explosive detonation velocities is shown ia Table 5. 

Explosive Detonation pressure, GPa Bulk specific gravity Detonation velocity, km/s Contains high explosives Heat of detonation kj /g Excavated vol relative to equal wt of TNT... 

In 1962, the first method for welding (qv) metals ia spots along a linear path by explosive detonation was patented (8). This method is not, however, used iadustriaHy. In 1963, a theory that explained how and why cladding occurs was pubHshed (9). Research efforts resulted ia process patents which standardized iadustrial explosion cladding. Several of the patents describe the use of variables iavolved ia parallel cladding which is the most popular form of explosion cladding (10—13). Several excellent reviews on metal cladding have been pubHshed (14—16). 

S. S. Penner and B. P. Mullins, Explosions, Detonations, Flammability andignition, AGARD Monograph, Pergamon Press, Inc., New York, 1959. 

Investigations in the field of shoek eompression of solid materials were originally performed for military purposes. Speeimens sueh as armor were subjected to either projectile impact or explosive detonation, and the severity and character of the resulting damage constituted the experimental data (see, e.g., Helie, 1840). Investigations of this type continue today, and although they certainly have their place, they are now considered more as engineering experiments than scientific research, inasmuch as they do little to illuminate the basic physics and material properties which determine the results of shock-compression events. 

Figure 4.9. Shock pressure versus particle velocity for engineering materials, geological material, and explosive detonation products. Intersection of detonation product curves with nonreactive media predicts shock pressure and particle velocity at an explosive sample interface. (After Jones (1972).)...

Dremin, A.N., Klimenko, V.Yu. and Kosireva, I.Yu., On the Mechanism of the Reaction Hot Spots Origin at Liquid Explosives Detonation, in Eighth Symposium (International) on Detonation, NSWC MP 86-194 (edited by Short, J.M.), Naval Surface Weapons Center, White Oak, Silver Spring, MD, 1986, pp. 678-687. 

Concerned mainly with the security of explosives and restncted substances. Applicable to the acquisition, keeping, handling and control of explosives, e.g. blasting explosives, detonators, fuses, ammunitions, propellants, pyrotechnics and fireworks. 

Chemical explosives detonate, or deflagrate. Detonating explosives (e.g., TNT or dynamite) rapidly decompose to produce high pressure and a shock front (travels faster than the velocity of sound). Deflagrating explosives (e.g., black and smokeless powders) bum fast, prodr er... 

Detonating explosives are primary or secondary. Primary explosives detonate by flame,... 

Zerkitiftung,/. cleavage, etc. (see zerkltiften). Zerknall, m. explosion, detonation, zerknallezt, v.i. explode, detonate. 

Mullins, B. P. and Penner, S. D., Explosions, Detonations, Flammability and Ignition, Pergamon Press, London, 1959. 

Diazotizations should be carried out above room temperature only in cases where a relatively dilute aqueous system (< 1 m amine, < 1 m mineral acid) is used and the diazonium salt formed does not precipitate (Bersier et al., 1971). Diazotization in highly concentrated sulfuric acid may involve a high risk of explosive detonation if carried out at a higher temperature (see Sec. 2.2). 

An explosive detonation occurs when potassium permanganate comes into contact with ethanol in the presence of sulphuric acid, if the medium is heated. 

In the No. 2 break test the explosive is fired almost unconfined. Under these conditions weak coal mining explosives detonate only partially and the probability of ignition of the gas mixture is reduced. Measurement of... 

A recent alternative to shaped charges is known as the squashhead projectile. As the name implies, this contains a plastic explosive which spreads on impact so as to make contact with the largest possible area of the tank before detonating. When the explosive detonates, reflection of the shock wave causes a scab of metal to be displaced from the inside surface of the armour plate (see p. 135). The effect inside the tank can therefore be greater than is the case with a shaped charge which may do little more than penetrate the armour. The amount of scabbing is approximately proportional to the area of contact of the explosive at the moment of detonation. 

Extremely explosive, detonation of a 1 mmol sample in a vacuum line led to impressive damage . 

Kuyper, J. et al., J. Organomet. Chem., 1976, 107, 130 Highly explosive, detonated by heat or shock. 

Sulfuric acid, which is useful for chemical delays and to ignite incendiaries or explosive detonators, can be obtained by concentrating battery acid. This can be done by boiling off the water in the battery acid in a glass or porcelained pan until dense white fumes begin to appear. This operation should be done out of doors and the resulting concentrated acid should be handled carefully. 

This keynote paper gives a general discussion of blast waves developed by high explosive detonations, their effects on structures and people, and risk assessment methods. The properties of free-field waves and normally and obliquely reflected waves are reviewed. Diffraction around block shapes and slender obstacles is covered next. Blast and gas pressures from explosions within vented structures are sumnarized. 

Scaling of the properties of blast waves from explosive sources is a common practice, and anyone who has even a rudimentary knowledge of blast technology utilizes these laws to predict the properties of blast waves from large-scale explosions based on tests on a much smaller scale. Similarly, results of tests conducted at sea level ambient atmospheric conditions are routinely used to predict the properties of blast waves from explosions detonated under high altitude conditions. 

Here, we concentrate on the gas pressures developed for high explosive detonations within vented and unvented enclosures, and these explosives plus nearby combustible materials. There is a voluminous literature on pressures and the effects of venting for confined explosions with only combustible gases and dusts in air, but that topic seems outside the scope of this book, and is not discussed here. 

The P-i Curve Concept and Applications. We hope that Section I of this chapter demonstrates the Dynamic and transient nature of the blast waves caused by explosives detonations, and the resulting pressure loads they can apply to various structures or objects. 

SHIELD DESIGN. In the initial approach to operational shield design, the hydrostatic pressure that would result from the MCI in the shield is determined. For a high explosive detonated in a... 

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