Explosive combustion

EXPLOSIVE COMBUSTION (EN: deflagration, blast burning; DE: Verbrennung, Schießbrennen; FR: combustion par explosion; ES: combustion detonante; RU: взрывное горение) is one of the forms of the explosive transformation of the substances of the different aggregate state, which is propagating with the subsonic speed (from tens to hundreds metres per second). The explosive combustion emerges during the ignition of the explosive substance, or during the explosive pulse of the low intensity.

The explosive combustion differs from the normal layer-wise combustion with the higher (by several orders of magnitude) speed, and with the variability of the parameters of the process (non-stationarity). The propagation of the flame proceeds as the result of the intense convective mass-heat exchange between the products of the combustion and the initial substance. Depending on the density of the substance, and on the speed of the process, there emerge during the explosive combustion the pressures from several hundreds (gases, aerosols) to hundreds of thousands kilopascals (the condensed explosive substances). In case of the progressive increase of the pressure, for example, within the enclosed space, the process is accelerated, and there emerge ahead of the flame the waves of the compression. In this case the explosive combustion may transition initially into the low speed detonation, and later into the normal detonation.

The explosive combustion is the characteristic type of the explosive transformation of the gunpowder, pyrotechnic compositions, aerosols of the industrial dust, and of the underground mine dust, of the different composition. In the mode of the explosive combustion, as a rule, there proceed the explosions of the methane within the underground mines. The mode of the explosive combustion is used for the practical purposes in case of the necessity of the "soft" load onto the rocks, for example, during the extraction of the dimension stone.