diffuusioliekissä

Diffuusioliekki, also known as a diffusion flame, is a type of flame where the mixing of fuel and oxidizer occurs in the flame zone itself. Unlike premixed flames, where fuel and oxidizer are mixed before combustion, diffusion flames rely on the diffusion process to bring the reactants together. This diffusion is typically driven by convection currents.

In a diffusion flame, the fuel is released into the surrounding air (or other oxidizer), and it gradually mixes with the oxidizer as it burns. The combustion process takes place at the interface between the fuel and the oxidizer. A common example of a diffusion flame is a candle flame. The wax is vaporized by the heat of the flame, and this vapor then mixes with the surrounding air and burns. Other examples include gas stove burners that are not properly adjusted for premixing, and the flames produced by burning wood or oil.

The structure of a diffusion flame is characterized by distinct regions. There is a fuel-rich region, an oxidizer-rich region, and a reaction zone where combustion occurs. These flames are often less efficient than premixed flames because the mixing process is slower, leading to incomplete combustion and the production of soot. Diffusion flames tend to be visually larger and more luminous than premixed flames due to the presence of incandescent soot particles. They are also typically cooler than premixed flames. The behavior and characteristics of diffusion flames are important considerations in the design of furnaces, engines, and fire safety systems.