What is a diffusion flame?

A diffusion flame is characterized by the manner in which fuel and air interact during combustion. In this type of flame, the fuel and air do not mix thoroughly until they reach the combustion zone. Instead, they move toward the combustion area independently, resulting in the combustion process occurring at the interface where the fuel vapor and air converge. This creates a unique flame characteristic where the reaction primarily happens in the region where fuel and oxidizer meet, rather than prior to that.

This concept is fundamental in understanding various combustion types and behaviors, making it critical for accurate fire and explosion investigations. Diffusion flames can be observed in many common applications, such as candles or gas flames, where fuel and air are progressively introduced to the combustion zone without prior mixing in a combustion chamber. Recognizing this distinction helps investigators analyze the dynamics of fire spread and combustion efficiency in different scenarios.