What is the term for air mixed with fuel prior to ignition?

The correct term for air mixed with fuel prior to ignition is primary air. This air is essential in the combustion process as it provides the necessary oxygen required for fuel to ignite and burn effectively. When primary air is mixed with the fuel before reaching the combustion chamber, it forms a combustible mixture that ensures efficient burning. Proper mixing and the right proportion of air to fuel are crucial for optimal combustion performance, which can affect energy efficiency and emissions from the burner or appliance.

Secondary air refers to additional air that may be introduced to the combustion process after the initial fuel-air mixture has been ignited, primarily to help complete combustion. Combustion air encompasses all the air used in the combustion process but does not specify whether it is mixed with fuel before ignition or during combustion. Auxiliary air typically refers to additional air supplied to assist with combustion but is not the primary air-fuel mixture being asked about in this question.