Editing Combustor (section)

===Air flow paths===
[[File:Combustor diagram airflow.png|frameless|border|upright=2|right]]
;Primary air
This is the main combustion air. It is highly compressed air from the high-pressure compressor (often decelerated via the diffuser) that is fed through the main channels in the dome of the combustor and the first set of liner holes. This air is mixed with fuel, and then combusted.<ref>Henderson and Blazowski, p. 110.</ref>
;Intermediate air
Intermediate air is the air injected into the combustion zone through the second set of liner holes (primary air goes through the first set). This air completes the reaction processes, diluting the high concentrations of [[carbon monoxide]] (CO) and [[hydrogen]] (H<sub>2</sub>),<ref name=HandB111>Henderson and Blazowski, p. 111.</ref> and also helps cooling down the gases from combustion.
;Dilution air
Dilution air is air injected through holes in the liner at the end of the combustion chamber to cool the flue gas before it reaches the turbines. The air is carefully used to produce the uniform temperature profile desired in the combustor. However, as turbine blade technology improves, allowing them to withstand higher temperatures, dilution air is used less, allowing the use of more combustion air.<ref name=HandB111/>
;Cooling air
Cooling air is air that is injected through small holes in the liner to generate a layer (film) of cool air to protect the liner from the combustion temperatures. The implementation of cooling air has to be carefully designed so it does not directly interact with the combustion air and process. In some cases, as much as 50% of the inlet air is used as cooling air. There are several different methods of injecting this cooling air, and the method can influence the temperature profile that the liner is exposed to (see ''Liner'', above).<ref>Henderson and Blazowski, pp. 111, 125–7.</ref>