Figure 2.3. Starting Fuel System.
Main fuel is delivered from the fuel control to the main fuel
manifold assembly by external lines. The main fuel manifold delivers
fuel to the fuel nozzles, which may be of the single or dual orifice
injector type, designed to introduce the fuel into the combustion
chamber. Some earlier engines use fuel vaporizer tubes in place of
the more efficient fuel nozzles.
On most gas turbine engines, fuel is introduced into the
combustion chamber through a fuel nozzle that creates a highly
atomized and accurately shaped spray of fuel suitable for rapid
mixing and combustion. Most engines use either the simplex or the
duplex nozzle. The exception to this is the Lycoming T53L11 engine
which uses vaporizer tubes in place of fuel nozzles. Each type of
nozzle is discussed in the following subparagraphs.