põlemus

Põlemus, Estonian for combustion, is the chemical process in which a substance reacts rapidly with an oxidizer, typically oxygen from the air, releasing heat and often light. It is a form of exothermic energy release and a central mechanism for converting chemical energy into heat, work, or both.

Chemically, combustion involves a fuel reacting with an oxidizer to form oxidized products and energy. Complete combustion of hydrocarbons yields carbon dioxide and water, whereas incomplete combustion can produce carbon monoxide, soot, or other compounds. A successful reaction requires sufficient energy to reach the ignition temperature and an adequate supply of oxidizer. The behavior of a flame depends on factors such as the fuel–oxidizer ratio (equivalence ratio), temperature, and whether the flame is laminar or turbulent. Adiabatic flame temperature is a key parameter in characterizing combustion.

Põlemus has widespread practical applications, including in internal combustion engines, gas burners, and industrial furnaces, where chemical energy is converted into heat and work. Emissions generated by combustion—such as carbon dioxide, carbon monoxide, nitrogen oxides, and particulates—are central to environmental and health concerns, leading to regulation and technology for improved efficiency and cleaner burn.

Historically, the study of combustion contributed to developments in thermodynamics and chemical kinetics, distinguishing energy release from mere oxidation.

See also: combustion theory, oxidation, energy efficiency, emissions.