nonpremix

Nonpremix refers to a state of combustion where the fuel and oxidizer are not uniformly mixed before entering the combustion zone. This contrasts with premixed combustion, where the fuel and oxidizer are thoroughly blended beforehand. In nonpremixed systems, the reactants diffuse into the combustion zone and mix through molecular and turbulent transport as they burn. This type of combustion is common in many practical applications, such as diffusion flames found in candles, gas stoves, and many industrial furnaces.

The primary characteristic of nonpremixed combustion is the spatial separation of fuel and oxidizer, leading to a diffusion-controlled reaction rate. The flame is sustained by the rate at which reactants can diffuse to the reaction zone. This can result in a flame that appears visually distinct, often with a distinct yellow or orange color due to incandescence of soot particles that form in fuel-rich regions. Understanding nonpremix combustion is crucial for designing and optimizing burners, controlling emissions, and ensuring safe operation of combustion devices. Factors like flow rates, ambient conditions, and burner geometry significantly influence the mixing process and the resulting flame characteristics.