Kustumine

Kustumine, or combustion, is an exothermic chemical reaction between a fuel and an oxidizer, typically oxygen from air, that releases heat and often light. Most combustion occurs with a flame, but it can proceed as slow oxidation without a visible flame, such as in coal burning or iron rusting. The process generally requires three elements: fuel, oxidizer, and sufficient energy to start the reaction.

When the mixture is right, the reaction propagates and releases heat. Complete combustion yields carbon dioxide and water; incomplete combustion occurs with limited oxygen or excess fuel and produces carbon monoxide, soot, and other hydrocarbons, with less energy released. The efficiency and cleanliness depend on temperature, oxygen supply, mixing, and residence time. Different flame types include diffusion flames and premixed flames, which control how fuel and oxidizer meet and transfer heat.

Applications include energy production in power plants and furnaces, propulsion in internal combustion engines and rockets, and various industrial processes. Fire safety focuses on managing heat, fuel, and oxidizer to prevent unwanted ignition and flame spread.

Environmental effects vary with fuel and conditions, but common emissions include carbon dioxide, carbon monoxide, nitrogen oxides, sulfur oxides, and particulates. Reducing pollution involves improving combustion efficiency and using emission controls. Historically, combustion was central to energy systems and has driven advances in chemistry and engineering.