What is an explosion? Concept and classification of explosions

What is an explosion? This is the process of instantaneous transformation of the state of an explosive, in which a significant amount of thermal energy and gases forming a shock wave are released.

Explosives are compounds that have the ability to undergo changes in the physical and chemical state as a result of external influences with the formation of an explosion.

Classification of types of explosions

1. Physical - the energy of the explosion is the potential energy of the compressed gas or vapor. Depending on the magnitude of the internal energy pressure, an explosion of different power is produced. The mechanical effect of the explosion is due to the action of the shock wave. Shell fragments cause additional damaging effect.

2. Chemical - in this case the explosion is caused by the almost instantaneous chemical interaction of the substances in the composition, with the release of a large amount of heat, as well as gases and steam with a high degree of compression. Explosions of these types are typical, for example, for gunpowder. During the heating, the substances arising as a result of the chemical reaction acquire a great deal of pressure. The explosion of pyrotechnics also applies to this species.

3. Atomic explosions are lightning-fast reactions of nuclear fission or fusion, characterized by the enormous power of the released energy, including thermal energy. The colossal temperature in the epicenter of the explosion leads to the formation of a zone of very high pressure. Expansion of the gas leads to the appearance of a shock wave, which is the cause of mechanical damage.

The concept and classification of explosions allow to act correctly in an emergency situation.

Action type

Explosives according to the type of action are classified according to the following types:

• Condensed;
• Three-dimensional.

The first type is those compounds which, under normal conditions in a solid or liquid aggregate state, can initiate a transformation reaction accompanied by the appearance of superheated vapors and gases with the formation of a stable high-pressure zone. A sharp expansion of the gaseous medium leads to the appearance of impact. Such reactions are called explosive transformation.

To start the reaction, it is necessary to inject explosives with some initial energy of mechanical, thermal, electrical, chemical or other type.

Groups of explosives

There are three main groups of condensed explosives.

Distinctive features

Explosions differ depending on the chemical reactions:

1. The decomposition is characteristic of a gaseous medium.
2. Oxidation-reduction processes imply the presence of a reducing agent with which the oxygen in the air reacts.
3. Reaction of mixtures.

To volumetric explosions include dust explosions, as well as explosions of steam clouds.

Dust explosions

They are typical for closed dusty structures, such as mines. Dangerous concentration of explosive dust appears during mechanical work with bulk materials, giving a large amount of dust. Work with explosive substances requires a full knowledge of what an explosion is.

For each type of dust, there is a so-called maximum permissible concentration, above which there is a danger of spontaneous explosion, and the amount of dust in grams per cubic meter of air is measured. The calculated values of concentration are not constant values and must be corrected depending on humidity, temperature and other environmental conditions.

A particular danger is the presence of methane. In this case, there is an increased probability of detonation of dust mixtures. Already, five percent of methane vapor in the air threatens to explode, which results in the ignition of a dust cloud and an increase in turbulence. There is a positive feedback, leading to an explosion of high energy. Scientists are attracted to such reactions, the theory of the explosion still does not give rest to many.

Safety when working in confined spaces

When working in enclosed areas with a high dust content in the air, the following safety rules should be adhered to:

- dust removal by ventilation;

- struggle against excessive dryness of air;

- dilution of the air mixture with inert gases to reduce the concentration of explosives.

Dust explosions are typical not only for mines, but also for buildings and granaries.

Explosions of steam clouds

They represent the lightning-fast state change reactions that generate the formation of a blast wave. Occur in the open air, in a confined space due to ignition of the fuel of the steam cloud. As a rule, this happens with the leakage of liquefied gas.

For security reasons, the following precautions are recommended:

- refusal to work with combustible gas or steam;

- rejection of ignition sources capable of causing a spark;

- avoidance of enclosed space.

It is necessary to understand soundly what an explosion is, what kind of danger it brings. Failure to comply with safety regulations and the illiterate use of certain items leads to disaster.

Explosions of gas

The most common emergency incidents in which a gas explosion occurs are the result of improper handling of gas equipment. It is important to timely eliminate and characterize. What does explosion from gas mean? It is due to improper operation.

In order to prevent such explosions, all gas equipment must undergo a regular preventive technical inspection. All residents of private households, as well as apartment buildings, are recommended to do annual WEDA.

To reduce the consequences of the explosion of the construction of premises in which gas equipment is installed, they are made not light but rather capital. In the event of an explosion, no major damage or blockages occur. Now you can imagine what an explosion is.

In order for the leakage of household gas to be easier to determine, an aromatic additive ethyl mercaptan is added to it, which causes a characteristic odor. If there is such an odor in the room, you need to open the windows, ensuring the arrival of fresh air. Then you should call the gas service. At this time, it is better not to use electrical switches capable of causing a spark. Strictly forbidden to smoke!

The explosion of pyrotechnics can also be a threat. The warehouse of such items must be equipped in accordance with the standards. Low-quality products can harm a person who uses it. All this should be taken into account.