What does excess air refer to in a combustion process?

Excess air refers to the additional air supplied beyond what is necessary for complete combustion of fuel. In a combustion process, a certain amount of air is required to burn the fuel completely and achieve optimal efficiency. However, in practice, burning a fuel generally requires more air than the theoretical amount to ensure that combustion is complete and to prevent the formation of pollutants.

This additional air, known as excess air, helps to ensure that all combustible particles are sufficiently oxidized. However, too much excess air can lead to inefficiencies and loss of heat, as the excess air absorbs heat that could otherwise be used for effective heating. Understanding the role of excess air is crucial for optimizing combustion processes in various applications, such as power generation and heating systems.