Explosive velocity
Encyclopedia
Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity
at which the shock wave
front travels through a detonated
explosive. The data listed for a specific substance is usually a rough prediction based upon gas behavior theory
(see Chapman-Jouguet condition
), as in practice it is difficult to measure. Explosive velocities are always faster than the local speed of sound
in the material.
If the explosive is confined before detonation, such as in an artillery shell, the force
produced is focused on a much smaller area, and the pressure
is massively intensified. This results in explosive velocity that is higher than if the explosive had been detonated in open air. Unconfined velocities are often approximately 70 to 80 percent of confined velocities.
Explosive velocity is increased with smaller particle size, increased charge diameter, and increased confinement.
Typical detonation velocities
in gases range from 1800 m/s
to 3000 m/s. Typical velocities in solid explosives often range beyond 4000 m/s to 10300 m/s.
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
at which the shock wave
Shock wave
A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
front travels through a detonated
Detonation
Detonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives, as well as in reactive gases...
explosive. The data listed for a specific substance is usually a rough prediction based upon gas behavior theory
Gas laws
The early gas laws were developed at the end of the 18th century, when scientists began to realize that relationships between the pressure, volume and temperature of a sample of gas could be obtained which would hold for all gases...
(see Chapman-Jouguet condition
Chapman-Jouguet condition
The Chapman–Jouguet condition holds approximately in detonation waves in high explosives. It states that the detonation propagates at a velocity at which the reacting gases just reach sonic velocity as the reaction ceases....
), as in practice it is difficult to measure. Explosive velocities are always faster than the local speed of sound
Speed of sound
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....
in the material.
If the explosive is confined before detonation, such as in an artillery shell, the force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
produced is focused on a much smaller area, and the pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
is massively intensified. This results in explosive velocity that is higher than if the explosive had been detonated in open air. Unconfined velocities are often approximately 70 to 80 percent of confined velocities.
Explosive velocity is increased with smaller particle size, increased charge diameter, and increased confinement.
Typical detonation velocities
Table of Explosive Detonation Velocities
This is a list of the detonation velocities at specified density of various explosive compounds.The velocity of detonation is an important indicator for overall energy or power of detonation, and in particular for the brisance or shattering effect of an explosive.-References:*Cooper, Paul W.,...
in gases range from 1800 m/s
Metre per second
Metre per second is an SI derived unit of both speed and velocity , defined by distance in metres divided by time in seconds....
to 3000 m/s. Typical velocities in solid explosives often range beyond 4000 m/s to 10300 m/s.
See also
- Table of explosive detonation velocitiesTable of Explosive Detonation VelocitiesThis is a list of the detonation velocities at specified density of various explosive compounds.The velocity of detonation is an important indicator for overall energy or power of detonation, and in particular for the brisance or shattering effect of an explosive.-References:*Cooper, Paul W.,...
- BrisanceBrisanceBrisance is the shattering capability of an explosive. It is a measure of the rapidity with which an explosive develops its maximum pressure. The term originates from the French verb "briser", which means to break or shatter...
- DetonationDetonationDetonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives, as well as in reactive gases...
- ExplosionExplosionAn explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...
- DeflagrationDeflagrationDeflagration is a term describing subsonic combustion that usually propagates through thermal conductivity; hot burning material heats the next layer of cold material and ignites it. Most "fire" found in daily life, from flames to explosions, is deflagration...
- Flame speedFlame speedThe flame speed is the measured rate of expansion of the flame front in a combustion reaction. Whereas flame speed is generally used for a fuel, a related term is explosive velocity, which is the same relationship measured for an explosive. Combustion engineers differentiate between the laminar...