What is the purpose of secondary air in combustion?

The purpose of secondary air in combustion is primarily to enhance the combustion process by providing additional oxygen that aids in the burning of combustible gases. When fuel is burned, the initial primary air mixed with the fuel is often insufficient for complete combustion, leading to the formation of unburned hydrocarbons and carbon monoxide. By introducing secondary air, there’s more oxygen available to facilitate the oxidation of these combustible gases, resulting in a more complete and efficient combustion process.

This additional air helps to optimize the combustion conditions, ensuring that the fuel is fully utilized, which not only contributes to improved efficiency but also minimizes the release of pollutants. Though it may have beneficial effects on emissions and fuel efficiency indirectly, the primary function of secondary air is to ensure that all available combustible material is burned effectively.