Deflagration and the transmission of detonation in certain British mining safety explosives

Deflagration and the transmission of detonation in certain British mining safety explosives by J. Plant Download PDF EPUB FB2

Combustion (burning) is a process by which energy is released. Deflagration and detonation are two ways energy may be released. If the combustion process propagates outward at subsonic speeds (slower than the speed of sound), it's a deflagration. If the explosion moves outward at supersonic speeds (faster than the speed of sound), it's a detonation.

Deflagration vs Detonation. Both of these are types of exothermic processes occurring in slightly different natures. The term ‘exothermic’ refers to the release of energy to the surrounding.

Both deflagration and detonation are ways of how the flow of heat and energy is being directed when dealing with combusting reactions.

Combustion is a “chemical reaction where the substance reacts. Applications. The phenomenon is exploited in pulse detonation engines, because a detonation produces a more efficient combustion of the reactants than a deflagration does, i.e.

giving a higher engines typically employ a Shchelkin spiral in the combustion chamber to facilitate the deflagration to detonation transition. The mechanism has also found military use in thermobaric. Discovered in by French scientists, detonation is the result of a supersonic wave initiating a secondary explosion.

Created by the primary initiation of a small amount of high explosives using friction, spark, flame, impact or electromagnetic radiation, this resulting shock front is powerful enough to launch a secondary explosion in. Chapter 3: Combustion, Deflagration and Detonation When a loud, sharp bang is heard similar to a grenade or a bomb exploding it is known as detonation.

If the noise is not as loud as that produced by a detonation and is longer in duration and sounds like a hissing sound (i.e. the sound of a rocket motor) it is classed as deflagration. As nouns the difference between explosion and deflagration is that explosion is a violent release of energy (sometimes mechanical, nuclear, or chemical) while deflagration is the act of deflagrating; an intense fire; a conflagration or explosion specifically, combustion that.

commercial explosives ranges from to g/cc. For free running explosives, the density is often specified as the pounds of explosives per foot of charge length in a given size borehole.

With few exceptions, denser explosives give higher detonation velocities and pressures. Density is an important consideration when choosing an explosive. A detonation wave is a very sharp, very high pressure, shock wave travelling through an explosive material.

It's followed by a zone of explosive material which is undergoing an exothermic chemical reaction. The shock wave itself is strong enough t. Explosives Detonation General This section deals mainly with pollutants resulting from the detonation of industrial explosives and firing of small arms.

Military applications are excluded from this discussion. Emissions associated with the manufacture of explosives are treated in Section"Explosives". Detonation Pressure- Based on detonation velocity and density of explosives a shock wave pressure that is built ahead of reaction zone is known as detonation pressure.

Higher the detonation pressure, higher would be the brisance capability (i.e. the ability to break or shatter rock by shock or impact). Its value varies from 5 to KB. Deflagration and Detonation Processes 7 History of investigations 7 Relationship of deflagratior and Jetonation 8 Detonation processes 11 Deflagration processes 15 Equations of state 20 Initiation and growth to detonatin 23.

A detonation may form via direct initiation or deflagration-to-detonation transition (DDT). The former mode is dependent upon an ignition source driving a blast wave of sufficient strength such that the ignitor is directly responsible for initiating the detonation.

The latter case begins with a deflagration initi. Deflagration and Detonation are terms used in the explosives world. They apply to materials that contain both the fuel and oxidizer that react when initiated.

The flame front of a deflagration moves at less than the speed of sound in the material. Inthis paper, the deflagration to detonation transition in explosives without theeffects of detonators was studied by the analyzing the accident in theproduction and storage process of explosives. Combining the decompositionmechanism of ammonium nitrate in the emulsion explosives and the lessons fromthe production of emulsion explosives explosion, the conditions of the emulsionexplosives.

Our staff actively serves on Industry Standards and rule-making committees, including the National Fire Protection Association (NFPA), Technical Committee on Explosives (responsible for NFPAExplosives Materials Code), the Committee on Combustible Metals and Metal Dusts (responsible for NFPA Standard for Combustible Metals, Metal.

Lightning continues to be the primary cause of premature initiations of explosives in mining; on average, over two such incidents are reported to the Mine Safety and Health Administration (MSHA) each year. The energy contained in lightning discharges and how this energy sets off explosives in mining.

Deflagration and Detonation Deflagration: • Subsonic, typically 1 m/s and 7 to 10 bar starting at ambient pressure Detonation: • Supersonic • High pressure shock front ahead of the reaction zone (i.e. flame) • Adiabatic compression – gas autoignites • Average pressure 15 to 19 bar (lean), 25 to 30 bar (stoichiometric) • Typical peak pressure up to 50 bar (but see later).

Detonation Systems Group, DX, Los Alamos National Laboratory, Los Alamos, New Mexico,U.S.A. Abstract The Chapman-Jouget and ZND models of steady detonation have proved most useful for engineering estimation of the propagation of near-planar, steady detonation in short-reaction-zone explosives.

Blasting safety demands the highest level of attention among employees working in metal and nonmetal mining.

Sinceseven miners have died at mines as a result of flyrock, misfires and toxic fumes. Two miners died in one incident in All mine operators, independent contractors and miners must follow strict explosives safety procedures to prevent fatalities.

Detonation and Combustion The release of energy (energy extremely useful for military purposes) is fundamental to both these phenomena. In both detonation and combustion, energy is released when a complex molecule is broken down into simpler constituent parts; however, as will be explained below, combustion is a much slower process.

High VOD explosives are more suitable in hard rock and low VOD in softer rock. Generally, explosives with a lower VOD tend to release gas over a longer period and consequently have more ‘heave’. The VOD range in commercial explosives is m/s. Density The density of a explosive determines the charge weight per meter of hole.Popular opinion that explosives transport is a very risky operation.

The holds authors decided to determine whether the hazards are as great as people believe. A search of the internet identified a number of explosives AN transport accidents, as shown in and Table 1. The more serious explosives transport accidents all occurred outside the U.S.Deflagration and Detonation.

There are two classifications of explosions that describe something about their hazards. These are deflagration and detonation.

• Deflagration is a very rapid combustion of particles of an explosive. The combustion begins at one or more points or on a surface and ‘burns’ at a very rapid rate through the material.