deflagracj

Deflagration, also known as deflagracja in some languages, is a mode of combustion in which a flame front propagates through an unburned combustible medium at subsonic speeds relative to the local speed of sound. The advance of the flame is driven mainly by heat transfer by conduction and diffusion of reactive species, allowing the surrounding fuel to ignite progressively as the flame front passes.

The rate at which a deflagration front moves, known as the burning or flame speed, is governed by chemical kinetics, heat transfer, and transport processes. In laminar conditions the flame moves relatively slowly, while turbulence or confinement can markedly increase the effective propagation speed. The process remains subsonic with respect to the unburned gas, in contrast to detonation.

Deflagration is distinct from detonation, where a shock wave compresses and heats the fuel–oxidizer mixture ahead of the reaction zone and the flame front travels at supersonic speeds. In practice, a deflagration can transition to detonation under certain conditions in confined spaces or porous media, a phenomenon known as deflagration-to-detonation transition (DDT). This transition depends on factors such as mixture composition, pressure, temperature, and turbulence.

Applications and safety concerns span a range of contexts. Deflagration occurs in everyday flames, internal combustion engines, and many industrial processes involving gas or dust mixtures. In safety-critical settings, preventing ignition sources, controlling confinement, ensuring adequate ventilation, and implementing dust suppression are common mitigations to limit deflagration risk and potential transition to detonation.