Difusioonipõlemiste

Difusioonipõlemiste is a phenomenon observed in combustion processes where fuel and oxidant mix and react simultaneously. Unlike premixed combustion, where fuel and oxidant are mixed before entering the reaction zone, in diffusion flames the mixing occurs at the flame front itself. This means the rate of combustion is limited by the rate at which the fuel and oxidant can diffuse together.

Common examples of diffusion flames include candles, oil lamps, and the combustion of natural gas in a Bunsen burner with the air hole closed. In these cases, the fuel vapor or gas diffuses outwards from its source, while the oxidant (typically air) diffuses inwards. The reaction occurs in the region where these two streams meet, forming a visible flame.

The characteristics of diffusion flames are distinct. They often exhibit a yellow or orange color due to the presence of incandescent soot particles, which are formed when the fuel undergoes incomplete combustion due to insufficient oxygen. The flame shape and size are influenced by factors such as fuel flow rate, oxidant availability, and ambient conditions. Diffusion flames can also be less stable than premixed flames and may lead to higher emissions of pollutants like carbon monoxide and unburned hydrocarbons if not properly controlled. Understanding diffusion combustion is crucial for optimizing the efficiency and reducing the environmental impact of various combustion systems.