What is the term for secondary air in combustion products?

The term "secondary air" refers to the additional air that is introduced into the combustion process after the primary combustion has begun. This air is not only essential for the complete combustion of the fuel but also plays a crucial role in reducing emissions and improving efficiency. In many combustion systems, after the initial burning of the fuel using primary air, secondary air is mixed with the combustion gases to facilitate further oxidation. This process can help ensure that all available fuel is utilized and that harmful byproducts are minimized.

Secondary air is specifically designed to enhance combustion conditions and ensure a more thorough burning process, which ultimately leads to reduced pollutants in the flue gases. Understanding the role of secondary air is essential for gas technicians, as it directly impacts the efficiency and environmental performance of combustion appliances.

The other options refer to different aspects of air involved in combustion: primary air is the initial air mixed with the fuel, tertiary air refers to any additional air added beyond the primary and secondary stages, and combustion air typically refers to the overall air needed for combustion but does not specify the sequential nature of its introduction.